No one has suggested this as yet, but you could as well just have a lemon on your hands, its those rare happenings where every once in a while you get a mean mugger that will strike at just about anything.

I suggest not trying to feed her for a week, then try offering food again, if you don't mind getting bit, I'd also suggest picking her up, if she's true to nature, she'll calm down once she see you wont harm her. You may also want to check on how the previous owner treats their animals... as this one could of gotten a bad encounter and decided to go rogue...