Does she train with anyone else? Tell your sensei and ask permission not to train with her anymore if she doesn't come around..
You can try this route, but I don't recommend it. I've seen this kind of thing happen before, and it can be extremely destructive to the dojo. You end up with this person who won't train with that person, and that person who won't train with someone else, and everyone developing resentments at a rapid pace.
Talk to your teacher if you can't work it out, but I'd recommend that you take it in the context of attempting to work out a solution rather than just cutting her off (I'm not saying that you would do that, but that's what was suggested).