What happened to the rest of the litter? Were all of them given away this young? Where did you get your puppy from?
Honestly, taking a puppy away from her litter at 4 weeks is a HUGE set-back, as far as bite inhibition, social interaction with other dogs, and general manners. Is there any way to get her back to her litter for at least a couple more weeks? Do you have any other dogs?
There are lots of great breeders here, but in general, if you're feeding kibble it must be soaked in replacement puppy milk or warm water and mushed up. A premium canned food (Innova, Natural Balance, California Natural, etc) would be ideal. She should be getting several small meals through out the day, at least 3 or 4.
My advice is to get her back to her litter, if possible. If not, get her around friendly, social, healthy dogs... as many and as often as possible! Make friends with neighbors who you know to have friendly dogs. Call up friends and relatives with friendly dogs. Of course, going to any public parks is a bad idea, until she finishes her shots at 4/5 months. Enroll in puppy play groups ASAP, as well as puppy kindergarten. The next 10 weeks of her life (especially the next 4) are essential in socializing her and teaching her manners, and interaction/play with other dogs and puppies is extremely important. Handle her often and act as a mother dog/littermate would. Yelp loudly or make a growly sound whenever her teeth touch your skin. Between 6-14 weeks, she should meet at least 100 people, and as many friendly dogs as possible, so definitely make an effort to socialize her!
It can be done, but raising a puppy that has been taken away from it's litter so young to be a well-adjusted adult is a lot of work! Good luck.