There is this thing ..... and it is called "Google" .....
search..... "increasing female breast size par diet" - TRY THAT.
Size for male and females, as far as I know, is genetic. There are hormones and estrogen that factor in.
Most people want something they don't have and are not happy with something they do have... but this quality IS what makes us attractive and individual. I would not worry too much. Eat healthy-veggies, fruits, milk, best for body and do some breast excercises maybe.
*Here is an interesting link but I do not know about any of this~ link