Breast Milk Issues (HELP)

Lorissa
Currently 2weeks PP, leaving the hospital two weeks back my milk supply was amazing after my colostrum passed but then after being home it seems after pumping my milk supply has gotten less and less. My son was born four weeks early so with him still being so little his latch isn't the greatest yet so I've turned to pumping and bottle feed him that way. 
Anybody know how to help my milk supply come in more ? Any certain foods or vitamins I need to be taking ?