P.M.
I would go back to nursing her. There are MANY things that can be done to stop biting, pulling the nipple, etc - - but it is usually started around 9 months. Good thing is that it is never too late!!
The main thing is to be CONSISTENT and PATIENT. You must ALWAYS do the same thing and to do it without yelling or anger towards the child.
1st infraction (biting or pulling away with nipple in mouth): say "Stop. No biting/pulling" and take her off and set her down for 5 minutes. If she still wants to nurse after that, allow her to.
2nd infraction: say "Stop. No biting/pulling" and take her off and set her down for 10 minutes. If she still wants to nurse after that, allow her to.
3rd infraction: say "Mommy said no biting/pulling. No more nursing" then set her down and walk away, do not nurse again for at least 2 hours.
Since you are starting this so late, I would talk to her BEFORE nursing, telling her she cannot bite or pull off of Mommy's breasts or she will not be allowed to nurse.
Edited: Nursing her to sleep is alright too... someone mentioned it was bad for the teeth - but that is not true. Formula in a bottle to bed is problematic because it pools in their mouth and sits there. When a baby suckles the breast, the milk immediately gets swallowed, so doesn't pool around and stay in the mouth.