I agree with the changing rooms idea. I know that at my old college there always was the opportunity to change rooms especially in situations like these. Reading this makes me angry and gives me the urge to tell you to tell her to "Bug the hell off" but I understand why you do not want to.
Please listen to the others and stick up for yourself. There is no reason for your roomate to beable to do whatever she wants... she needs to be put into her place.

Jessica