Speaking from experience:
As others have stated, get a lawyer now. DO stay in the house or there is a very good chance of you not getting back in. If she is in the house, then you will get stuck paying her the mortgage/rent all the while also paying for where you are staying. Better to make her pay you.
Prepare yourself for the legal process. It is NOT like you see on TV. Don't count on or expect the judge to be fair, unbiased, attentive to your concerns or even be fully aware of the law. Women always have the advantage in divorce cases so you will be fighting from behind in court.
Document EVERYTHING. Try and contact her only with E-mail that way you have a firm record of everything and when it was said. If you do have verbal communications, write it down in a log with the date.
In my state, the court OWNS all of your property and (effectively) your body. It has control of every aspect of your life. Expect the arbitrary rulings of the judge to severely impact your day to day life.
Your future is now in the hands of a person that you don't know, doesn't know you, and really doesn't care to. Unless you are wealthy, your case is just another that day they have to deal with.
Get it over as soon as possible. Make as many agreements out of court as you can. You DO NOT want the judge making decisions for you.