Dude your story almost sounds like part of the story my crazy buddy went through last year. His GF ended up being a phsyco illegal allien from Mexico too. I sooo wanted to call her in and have her deported to save him from her, I wish I would have done it now cause she cause so many problems for him too.
Beleive me she will not stop, everytime you think she has reached a new high, she'll think of something worse. THe way things are going I'd say it's mimiking my friends troubles. So don't think I am paranoid or something, go and get a PPO from her. Make up some BS story if you have to with the cops but make her be the guilty party first. Don't instigate things with her, just get away from her. Then when $hit hits the fan and trust me it's not "if" it's "when" at least you will have some backup. My buddy ended up in trouble with the cops and got thrown in jail cause the cops got called to their argument and thought he hit her. He didn't touch her yet he still got in jail for 2 days and had spent tons of $$$ to get a lawyer and prove himself inocent.