H.,
I'm so sorry you are going through this awful stage in nursing. You are doing such a great job getting some support and trying things out. My son did this when he was mostly done nursing, but was still just hanging out on the breast. I learned to recognize the cues that he was about to bite and then end the feeding. When he got me, I'd unlatch him, firmly tell him no biting and end the feeding (even if it just started). I wouldn't let him back on until enough time had passed that it felt like a whole different feeding instead of just taking a break. The other trick you can do which isn't intuitive, is to smoosh her face into your breast when she bites. She'll need to open her mouth to breathe and you can take her off. I've never done this, but have heard it at La Leche League meetings and apparently it's pretty effective. It sounds like she thinks it's a game right now, so you'll want to figure something out quickly to let her know this is not ok. Once you figure out what that is, this behavior shouldn't last long.
Good luck!
S.