When Taycie was about that size she ate 1/4 cup twice a day so 1/2 cup daily.. I do bring her to work with me so when she was little I split it up between 3 meals.. Usually her "lunch" meal I just gave her out of my hand as a treats
It was eaiser this way because I did not want the other dog at work eating her food.
I think I would just watch her poop, activity level and weight.. if everything looks good and she is continually gaining weight at each vet appointment right now then you are doing great!