PCOS is the one of the common cause of the primary infertility
and obesity is the associated feature with PCOS. other features include male type hair growth on face and body. the drug about which your friend have told you is basically an ovulation induction
drug. certain other drugs exists like bromocriptine
but there is not guarantee this can help because lots of gynecologist have tried this in clinical practice but don't have gained any significant results.
what you can do is try to loose your weight and before taking any self medication
, first consult your gynecologist as there are more concerned with your health then your pregnancy