5 weeks is way to early to take a puppy away from mom or litter mates. You may end up with a very sick puppy and big expenses. I understand if the breeder has personal problems and needs you to take the puppy, but what's she doing with the other pups? You will have to care for her 24 hours a day.
Belle came from a litter of 7 that overwhelmed her Yorkie mama and she started being mean to them so they kept her apart from the babies. Belle was well taken care of and with her litter mates until 12 weeks. Even if she could keep them until 8 weeks, but still then get an agreement about the puppies health and expenses and take the little one to the vet right away. Keep in mind, as much as you want this puppy, you are going to get very attached to her and it's going to be even harder to lose her when you have been taking care of her. I hope you don't let her pressure you into taking the puppy now, be careful of what you're getting yourself into