Metformin and PCOS ????? Help Please?

Hi, My Dr put me on metformin 1500mg a day to help with my PCOS, where my periods are irregular... He tried me on Clomid also, and it didn't work, so he referred me to a specialist, which I go to in Febuary... The Metformin thus far seems to be doing it's job for the past few months with my period, espically concidering i never had a regular period on my own since i was 18 years old...but my question is, can someone with PCOS get pregnant, just taking the Metformin??? My Dr is suggesting Invetro Fertilization, but I want to try the shots, could anyone with any helpful advice please help fill me in on all of this???? I just feel so lost and I don't know what to ask my new Dr. I am So Confused and Frustrated... Also, I am over weight and have been changing alot of my old eating habits and i have currently lost 8 pounds... Does weight loss really increase your chances of conceiving????