Thank you guys so much for all of your concern and advice, I really do appreciate it.
At everyone asking if it is worth it to go after it, I'd say yes. I honestly don't plan on having a relationship with him after I go off to college, because he's very manipulative and he sleeps and breathes mental abuse/manipulation tactics. I can't deal with him anymore. In fact, doing this would probably push him to let me live with my mom, which I already want to do anyway.
More on the computer -- a hinge had popped out, and a few weeks later the uneven balance of the computer caused the other hinge to bust, I guess. I did plan on buying a laptop with that money, though, but:
a.) I probably won't like the laptop they're forcing on me, or
b.) They WILL find some reason to not give me the laptop, because that's the kind of people they are.
I'm going to the bank tomorrow to see if I'm allowed to withdrawal whatever money is left. I'll keep you all updated if you'd like. Thank you once again for all of your advice, I'll weigh everything carefully. =)