When is your oncologist able to determine the stage of your ovarian cancer?

During the last 6 months I have had several sessions of chemotherapy to treat ovarian cancer. Three weeks ago, I had surgery: removal of ovaries and omentum. My post operative appt. is in a couple of weeks. What questions should I ask my doctor regarding "stage" of cancer? What exactly does "stage" mean and what are its implications? Thanks for any help you can give me.