Weight loss is immensely beneficial for women with PCOS. Getting regular menses is a good sign and trying during ovulation time will help. For better timing you can use the ovulation calendar or ovulation detection kits. If this does not help then do consult your Doctor as women with PCOS often need help for conceiving.
The answer is based on information provided. Exact advice is not possible without a proper examination and investigations. You are requested to consult your Doctor. Take care and keep us posted.