As others have said, get her out as quickly as possible. If she has a friend who can take her in, send her there now. Put her crap in a storage locker and pay for the first month. allowing her to stay on your property opens you up to liability if she somehow gets injured. It also gives her a chance to do something to get even.
As soon as she's gone, change the locks.
Don't put up with any bullshitt. You've given her plenty of opportunity to change and she chose not to. Softening up, feeling sorry for her and allowing her to drag this out, will only hurt you.
There's a time to be compassionate..........now isn't it.