what Amanda said is right- i was suffering for PCOS, and was on Metformin 500 Mg- the doctor gives the prescribed doses as per the body type- usually they give 1000-1500 Mg (2-3 tabs) a day to see , but for me 500 Mg worked well to have regular periods and Ovulation. the time i got pregnant, my doctor took me off from Metformin and i am only taking prenatal..
Metformin helps to ease type 2 diabeties effects, which can go hand in hand with PCOS. Next, clomid is to help increase your chance of actually ovulating an egg each month, with is another problem with PCOS. You should discuss these things with your doctor before taking any prescription medication. Each of the medications you mentioned have a specific dosing that is important to follow.