Congratulations on you new furry additions!
It would be important to make sure that your dog is not interested in eating her food due to an underlying medical condition, so an evaluation by the vet, would be a good idea. If she's drinking, eliminating and taking care of her puppies normally, then she's most likely feeling alright. However, the fact that you said she IS interested in people food shows that she does have an appetite, so that's good.
Yes, nursing dogs (and pregnant dogs) should be fed puppy food for it's higher caloric content. Try not mixing wet dog food with the puppy food, but just feed her a high quality puppy food (canned would be preferable, but you can give dry as well), and see if she likes that better. Also, you can mix the puppy milk into her food, if she likes the taste, or offer it separately; don't mix it in her water, just offer fresh, cool water for her to drink. She's losing fluid through the nursing, so she needs to replenish it.
Some healthy, tasty brands of puppy food are Wellness, Newman's Own, Halo, Natural Balance, Canidae, and many others which are available at your major pet supply stores. These brands contain no artificial additives or preservatives and no common allergens.
Try to entice her by mixing some plain boiled chicken breast or turkey (no seasonings/no onion or garlic) into her puppy food; show her you're doing this, so she'll be excited about it. You don't want to encourage her with the table scraps, but she does need to eat, so try that method. Also, offer her some Nutri-Cal or Nutri-Stat, a nutritional supplement that will add calories and energy and might act as an appetite stimulant. You can find it in major pet supply stores and/or online.
If she continues to be picky and not eat as much as she should, definitely have her evaluated by her vet, to make sure she's doing well, medically.
I hope all will be well with your mom and puppies!