I will be picking up our new puppy Jessie in 2 days. She is a 10 week old chihuahua. I spoke with the owner today(not a breeder, just a chi owner whose dog has had puppies). They are not in a position to provide the caliber of food which I would like to provide for her. She has been eating a mixture of gravy train

and alpo canned puppy food

. I would love suggestions on how to change her food. I hate to continue with such low caliber dog food. Do I mix new with old? Can anyone recommend a favorite puppy food? I have another dog who eats Natural Balance limited ingredient dog food and occasional raw patties. He is a wheaten terrier and 7 years old so obviously will not be on the same diet.
I am very interested in opinions on best quality food out there. Money is not as important as quality of nutrition but I would love a good deal

Also recommendations of portion size and recommendations on frequency of feedings would be greatly appreciated. Thanks so much!