Breeding just because isn't a good idea, worry about the babies you have now. They should not be handled for quite some time.
They should be separated at 3 weeks, each baby into a different cage. Most hamster species cannot live harmoniously and they can be hard to sex especially when young, the last thing you want is a baby girl impregnated by her brother in her first heat, it could make her sick or kill her and her pups.
When they are young make sure they get a high protein diet, this goes for mom while she nurses also. Egg is excellent for this, just scramble it with no oil or butter and give small pieces every day in her dish.