I think Karen has the right idea, definatly set the rules now because she is walking all over you and she must obviously know it, my little brother even knows you dont leave rooms in a mess especially when you have made it and hes 9 years old.

I would defiantly write up a list as Karen suggested or make her pay rent or move out, no one else would put up with the kind of behaviour so you definatly deserve to be treated better seeing all you have done for her.