I would be very cautious if i was you, so this lady doesnt breed the puppies herself, just buys them from a breeder and then sells them?
I think it would be best really to buy from the breeder to cut out the middle person as it could cause problems if the potential puppy got sick with a herridatory illness.
But i mean go check her out if you like, everything could be fine, just be careful as there is the ''dark'' side in the world of dogs