Dear Dusty, sounds like a bunch of stuff is going on with her. Drinking would just aggravate any other stuff and freeup the violence. I agree with the previous posts, she needs help.
The only time anybody could approach her is when she's sober. Can't imagine if she would listen to you or not. The main thing now is for you to take care of yourself. Do you have a friend you could call on an immediate response basis in case she comes back to your place (angry)? I would like somebody there with me, myself, nomatter what condition she was in... There is no excuse for violence. Take precautions now, plan ahead while it's not the heat of the moment.

It might help to work with a councelor yourself to get a hold of your end of the situation. Is there a domestic violence hotline in your area? They would be versed in services available in your neck of the woods. Best to you.