Thanks everyone.

You are right swansonbb, I do know what I need to do, but that doesn't make it any easier. I'm very used to letting people walk all over me unfortunately. I need to stop treating her like she's my little sister I need to protect and start treating her like the adult she is (or should be).

Tonight I will be laying down some rules and failure to comply with these rules will ultimately result in her eviction from my apartment.

The reason I have only asked her to pay half of the electric and half of the grocery bill is because I really wanted her to save up to take some courses at one of the local colleges, but since she seems to have no real interest in pursuing that, I will be changing that arrangement. I was also buying her cigarettes because she's miserable to be around when she's going through nicotine withdrawals.

If I make her pay for half of everything (rent, utilities, food, etc...) is it unreasonable to still lay down some house rules? Such as, if you aren't comfortable meeting a guy for the first time at a restaurant don't bring him into the apartment because you don't know him well enough?