Wow, only with littlemansmom have I seen such unilateral agreement.
I can't believe we live in an age where young people seem to feel that have so many "rights" against their parents, particularly young ones who are old enough where their parents no longer have legal obligations to them.... Sigh...
Find a sublease, get a job if you don't have one, throw your crap in your car (hopefully you actually own your own car) and get a move on sister... Thats really your best course of action. Your parents picked fido. That sucks. Get over it and be a grownup... or deal with the dog...
Legally you have remedies but they aren't ones that are going to give you the desired outcome.