I hate to tell you this but she's a baby and thats what babies do. Yelping is a good idea, she will learn from this but it will take time. Right now one of the few ways she has of interacting with you is by using her mouth. You can try giving her chewies to munch on instead of your hand, but again she's just doing what babies do. If you can find a way to enjoy this special time, they grow up so fast and before you know it she will be grown and all you'll have are memories of this special time.