If that's the case then the answer is take them back where you bought them from ;)
Puppies aren't just rehomed when they can eat solid food, they actually need to be around their litter mates and mother to learn valuable life lessons. Dogs that are taken away from their mothers too early can have serious behavioral problems... not something you want to deal with I'm sure.
What you have done is actually illegal... not by you, but by the breeder. They can get in serious trouble for selling puppies so young. I would report them to the SPCA or even the Police.
Did the breeder give you any information at all about caring for them, or just hand them over?
If the breeder has suddenly 'vanished' as many people who do things illegally seem to do. Then do we need to start with the very basics? Or do you know a bit about caring for weaning puppies?
Here is a good site with basic puppy care.
If you need more detailed information just ask:
http://www.dog-names.org.uk/puppy-care.htm