Ah yeah. Another person that thinks so highly of themselves it's not funny. Tell her off. That's what I'd do. Actually, if it was bloke, I'd get into a fight with him, but thats another story altogether.
Basically, just don't let people treat you like that. Demand some form of respect.
Ask round and see if other people are sharing your opinion about her, and if they are, join together to tell her off, since it'll be harder to say anything too discriminating when you've got friends around you.
But also, remember that she might be going through something tough now herself. A lot of people don't act like donkeys just coz they want to (although there are a select few who do). Usually, the person has experience some form of trauma, and is trying to make themselves feel better. Maybe she was treated the same way before? I dunno.
So tell her off, but don't make her feel too bad. Sometimes the person may not even realise that they're being hated by someone. Tell her gently about whats going on. Then if that fails, either tell the principal or a trustable teacher about how you feel, or just start with the nastier tactics.