Wow, the breeder let her go pretty young! Usually it is at leas 8 weeks and some won't let them go until 10-12 weeks! As for her weight now, that sounds about right. I have never heard of feeding a young pup once a day! You are doing the right thing by splitting the meals up, and you could even go to 3 times a day. I was feeding 1/2-3/4 cup three times a day at eight weeks. When I picked up our pup at 8 weeks, he was 10 pounds, so she is a healthy size. As for the food, well, check out the food ratings on this site. It will give you a ton of info, and there are many knowledgeable food gurus here to help. As for the breeder, doesn't sound like he or she was very reputable. Even at 6 weeks, that is a little young to be given away. But, Gracie is lucky to have you as her papa! Good luck! There will be others along soon to give some good advice! Gracie is beautiful by the way!!!