Surely if you don't like them, you would want them to know that you don't like them, so that you don't have to hang around with them?
I don't, I've got other friends. She keeps talking to me.
apart from outrightly telling her that you don't want to spend time with her anymore all you can do is either, put up with it until the end of college, or try to distance yourself from her as much as possible until she looses interest or gets the hint.
as for her friend, what is she a Llama? I mean what self respecting person spits at people?