I agree. You need to encourage her to bite toys by getting her interesting stuff - maybe toys with catnip or little colored balls -
Kittens play this way. I know it is tough to deal with because they need to be taught limits, which momma cat or their siblings would certainly do by yelping when the biting has become way too hard. You could do the same. I used this technique to teach my cat boundaries.
One more thing you could do is stop playing with her when she bites too hard. Just ignore her, turn your back on her. She'll get it.
Another thing you could do is water. The only thing is you'd have to have a bottle with water always handy so that when she bites you, you can spray her. This works very effectively, but you'd have to go around with a bottled water near you :)
give her a toy to bite on instead and; she's a kitten, she's playing. she would normally do this same thing with her litter mates who would cry if she bit too hard, and that way she would learn how hard is too hard. make sure that when she bites, you cry out (high-pitched mewling cry like a pained kitten would do) and she will learn not to do it.
this same technique works with dogs :)