Since your wife is already 33 years old and have tried pregnancy
for past 4 years under the guidance of doctor,I would advise you to go for assisted reproductive therapy like IVF or ICSI
There is no point waiting time as PCOS
is a very tricky and complex situation and one can't be sure of pregnancy by natural means.
Consult a Gynecologist who is specialising in this field and discuss with her.
Till you consult a specialist I would advise your wife to go for regular aerobic exercises and shed weight if she is overweight
It is said that even a reduction of 10% weight can regain the fertility