She is now almost 4 months old so 3-4 feedings per day depending on your schedule would be fine. Typically an 8 lb pup would eat 1.5-2 cups per day but I am not much for measuring food. Here is some info that will help:
There are a few guidelines of adequate consumption that are just as important as the actual volume of food eaten. Allow your puppy to eat whatever it wants in about 5 minutes or so. Keep in mind your puppy's appetite will vary during the day, and day to day, just like us.
Once you are confident your puppy is eating regularly you can begin reduce the number of feedings. By the end of the second week shoot for about 4 feedings per day.
Your puppy's attitude will generally tell you if he is eating enough: if he eats regularly, eliminates normally, plays energetically for a while and then sleeps things can't be too bad. If you feel there are changes to this pattern let me know as it could be a signal that something is up. A decrease in consumption coupled with a decrease in activity spells trouble.