J.,
Opinions and philosophies on breastfeeding past a year are mixed, and everyone's entitled to their own. I see nursing past a year to be just fine as long as EVERYONE involved wants to continue. If you are ready to stop, and her hurting you is a real good reason, then wean her. Some people go for a don't ask, don't refuse method, where if the baby asks to nurse, either verbally or with gestures, you let her, but you don't sit down at regular times or offer the breast. Others start offering a sippy cup of milk just before typical nursing time to fill her belly and replace that part of her habitual routine. Some Moms go cold turkey, just stop, and say no. It's rough for a few days, but they survive. The method is all up to you. If you are ready to wean, then feel free to do it. You've done a great job nursing her, and her health will benefit from your efforts for avery long time. Congratulations to you!
If you don't want to wean, then really the only method is to remove her from the breast when she bites, tell her No Biting! and not let her continue. There aren't a whole lot of other options on that.
Jess