Emancipation is a legal procedure basically divorcing you from your parents. If you are in foster care you are a ward of the state and it depends on the state you are in. Your local courthouse or a family lawyer would be your best bet b/c of local legal differences.
However, where you going to live? No-one under 18 can sign a legal contract, even if emancipated as far as I know. Every apartment needs a lease contract.
My g/f in high school went through this. I know from experience how much the f/c system SUCKS. BUT, if you can hold out I would. No parent/youth situation is good because parents don't remember that "kids" are really adults in training. The child association assumes ignorance and that is not the case.
IF there is abuse, document it and go to your case worker. IF it is a clash of personalities, try to work them out, it can be a great training lesson for conflict resolution in the future.
I am willing to work with you pro-bono tomake some plans and changes to help you in your current situation