What do I do?

OK, so that job I was so excited about has turned to poop. This is going to be long and not very uplifting, but I need to vent (and hopefully get some advice, if there's any out there in internet land)

Basically, two people are leaving the DT department - one is the food teacher and current head of department, the other teaches graphics. When I interviewed and spent the day with the new head of department, we talked about Graphics and Resistant Materials (like NSW's Industrial Technology), checking out the workshop that I would be taking over, talking about units of work that I had worked with, new ideas, etc. I took the job with the understanding that I would be teaching mainly Graphics with some Resistant Materials and they would be continuing to seek out a Food specialist.

I talked to the new Head of Department a couple of times over the 2 weeks between the interview and the induction day last week. He told me they had hired someone who was great and experienced and all that, but that as a result, I might have to teach some Food. I reluctantly said that was OK (what else could I say?). The next time we spoke, he said that it looked like my timetable would be mostly food. I wasn't excited or positive about this, but said I could handle it as long as I got to teach something else as well. He assured me that I would still get to spend some time with the A level Product Design group at least. I wasn't very excited about the job anymore.

By the time I got to the induction day last Tuesday, the timetables were done and I had nothing but food. OK, I exaggerate - I have a form group (like roll call/home room) and one class a week of what I would've called Health when I was in high school (you know, the theory stuff you do in your PE class, like living skills, sex ed, citizenship, etc - yeah, random whoevers teach it here, with VERY little help or guidance [read that as 'I had no idea what we were doing or why']).

OK, I thought, this kind of sucks, but I'm here now, I can handle it. I spent Tuesday afternoon, after the official inductiony bit (which was not very helpful in getting us prepared for starting less than a week later) helping them to transfer a bunch of stuff from another school that is closing down - heaps of materials and things that I would never get to use working in the Food room.

I met with the current food teacher on Thursday to discuss the schemes of work and all that. None of it was super appealing to me, but it seems to work and I was fairly sure I'd be able to run with it, making changes where I thought I could or whatever. I didn't look at it and think, this is a great starting point and then I will add my own flair, like I usually do though. It was more like, I have to run with this, otherwise I will be spending every waking hour between now and September trying to work out how on earth I am supposed to teach Food Tech every day of the year.

On the weekend, the whole gravity of the situation hit me and I ended up in tears, several times.
I had accepted the job because I thought I'd be teaching the areas I know best. If they had said to me "We'd like to offer you a job but you have to be the Food teacher" I wouldn't have taken it. I have nothing against food or the people that teach it, but I am a trained DESIGNER and Food Tech is not design, even if you set creative projects.
Tying into that, I feel as though I was misled and/or cheated out of a job. Not just the job I thought I had accepted (at this school, teaching what I know), but also any other job I could've got between then and now (at another school). I actually had an interview lined up for the following day with a trial class teaching a GCSE Graphics class - I doubt they would've hired me and then made me teach food...
I'm so disappointed that I focussed on applying for jobs at Christian schools because that's the environment I want to work in, where I know I have the opportunity to help young people see Christ, and then I get treated worse than anyone has ever treated me in a professional capacity.
I have two GCSE classes, one in each year, and I don't feel as though I can provide the education they need or deserve, especially after seeing the current food teacher in action today (she's an awesome teacher and food is her speciality, so she really knows what she's talking about) - I just don't have the knowledge or skills myself, so how on earth am I supposed to pass everything onto the students?

To make my misery complete, we got a phone call this morning to say that Graeme's Great-grandfather had passed away. In itself, this isn't life-shattering - its sad, yes, but he was very old and ill. It was more the hitting home of the realisation that we are so far from home and the people we love. This was literally as I should've been walking out the door.

So I get to school later than I wanted to and feeling pretty bad, but somehow, I can't bring myself to say anything to anyone, almost hiding behind the death as the reason for my being a bit off. That was, until lunch time, when the new Head asked me how I was going and I simply said "I'm not very happy about having to teach food". It spiralled from there - pretty much everything I've said above came out. The current Head of department (remember, she's also the food teacher) had no idea any of this was going on because she had basically been kept out of the whole process. She has been great - sympathetic, understanding, supportive - I wish I was going to be working with her.

So after talking to them and going through everything, I basically feel like I need to get another job. The other person who has been hired in was appointed by the Head (Principal) and is basically getting whatever she wants, simply because of the other skills she brings (she'll be a head of year and has extra qualifications) and she doesn't WANT to teach food, even though she has experience doing so. They've said they can shuffle some classes around but I won't lose the GCSE, which is the classes I'm most concerned about (I can teach junior DT in any area, no issue). I feel like I'm being pushed out of a job that I was genuinely excited about and am angry, hurt, annoyed, but mostly just sad.

So what do I do?
Its going to be even harder to get a job now, because there are like 3 weeks left until summer and most positions for next year are filled. I need a job, but not badly enough to risk my sanity for it - we can survive on Graeme's income, but there's not a lot left spare. I don't want to do day-to-day teaching because it sucks and I'm not enough of a nasty teacher to make it work for me.
Do I stick it out until I can find something better?
Do I just call them and tell them to shove it?
Help, please.