PCOS is an endocrine problem affecting almost 10% females and one of the leading cause of female subfertility. Since its etiology has been linked to insulin resistance, glucophage(metformin) forms one of the treatment. If you are planning for a pregnancy, consult your gynecologist regarding ovulation induction drugs to help to become pregnant.
Glucophage(metformin) can be safely taken during pregnancy and in fact it increases the chances of pregnancy, reduces the incidences of miscarriages and increases the live birth rates in pts with pcos.

Diane 35 helps regulate your periods and reduce the hormonal problems of PCOS like excessive testosterone, LH and Estradiol. Glyciphage is a brand name of Drug Metformin that reduces 'inslin resistance'....thus correcting the underlying problem in PCOS. Taking Metformin has shown to improve the response to many drugs your doctor will give you and thus increase your chances of getting pregnant. Also Metformin might help you to lose some extra weight, if you combine it with a proper diet and exercise schedule.
Coming to your question, can you start trying for a pregnancy immediately without 3 cycles of treatment? Answer is yes, but the results will be less succesful.