Am just assuming when you let her in you didn't understand her situation, besides she's your friend, I don't see any essence of dragging in another third party in your issues. The best thing to do is try talk to her about the 30 day notice.If its not yet over, give her sometime as you try learning her moves and who she goes out with. When the thirty days will be over, please remind her and tell her its time to leave and you need to be serious no matter your friendship.
A good person will definitely leave. If she doesn't leave then you'll have to involve the authorities and explain to them how it started. Though it might not be the best solution to such a close friend, but at least you'll be safe and yours stuff secured.