Dear Mama Mary -
I have a problem. My roommate won't leave the living room. She sits on the couch watching Cartoon Network and eating crap that leaves crumbs all over, and the room is starting to smell like ass. I asked her to clean up after herself, and she did a little, but by the next week it was worse, because she spilled bong water on the carpet.
Mama Mary, what should I do?

Dear Daughter -
First, I have some questions for you. Do you have a lease, and if so, is she listed on it? If so, you can't just say "This isn't working out, find someplace else." You'll have to confront the problem. There's a world of difference between being a slacker in your downtime and having nothing but down time, but you can't fix other people, only the way you handle your interactions with them.
Sit her down & hammer out House Rules. Your biggest complaint seems to be the smell rather than the Cartoon Network, so maybe work out cleaning duties. If the House Rules don't get followed, enforce consequences. If you can't do this, resign yourself to living out the rest of the lease unhappily and invest in Febreeze.