KK's mom, first, I am SO sorry your 8 yr. old was stolen....how sad.
I'm sure you are VERY anxious to bring home your new little baby.
My Sophie came from a litter of 4 too and the mom dog stopped nursing them around 7 wks. That is why the breeder (so kindly) let me take her home just before she turned 8 weeks. (She knew that I would be with her 24/7 as well and she also knew how much I wanted to love and care for this puppy properly.)
If you are able to bring her home (and I hope you are), then I would really try the switch to the Nutro. (My puppy ONLY likes the canned food. She does NOT like the dry kibble with water to soften it up at all.) Since this is not your first Yorkie, and since you seem knowledgeable, then maybe she will let you bring her home. Also, you will be with her 24/7, so that should make a big difference too. Do you know how much she weighs now?
I was talking with my girlfriend's today and I told them that I feel like I've become a dog food expert in the last week
....it's amazing how much difference there really is in the different brands.