Please don't do it. No responsible breeder ever removes a puppy from its mother and litter before 6 weeks, and 7-8 weeks is much better. At that age another week is a long time, 20% of the dogs life. There are important lessons on being a dog puppies learn from each other at that age.
This sounds like the Mexican puppy mills I have heard of. The breeder may not have chosen breeding stock likely to produce sturdy, healthy dogs. Poorly bred dogs have more health and behavior problems. Try to find a good American breeder.
One of the best sources for dogs with a predictable personality is the rescue
dogs. These are dogs that lost their home, but were taken into a foster home
to be retrained as necessary and placed in the right home for them. You may
find a rescue near you starting at
American Kennel Club - Breed Rescue The rescues charge a fee to help cover their expenses, but is much less than the price of a puppy plus all its medical expenses the first year.
Petfinder.com: Adopt a pet and help an animal shelter rescue a puppy or kitten. have even more dogs, but don't do as much retraining or as careful placement as the better rescues.