M.R.
Although my situation isn't the same as yours, I HIGHLY recommend buying and reading Toni Weschler's "Taking Charge of Your Fertility" and/or going to www.fertilityfriend.com.
Many people on this site swear by the book and, quite literally, within two months of getting and reading the book I got pregnant. My history goes a little something like this: I have PCOS and I did about 3 years of fertility treatments and we NEVER saw more than one ovum dominate, even though we did varying levels of Clomid and injectables. Throughout the process we did conceive once but subsequently miscarried. On a break from fertility treatments we managed to get pregnant and now have a 2 year old son. Fast forwarding to the present, my husband I knew we wanted to start trying again but I wouldn't be able to do fertility treatments til summer. I bought the book and started using the fertility friend website to chart my cycles. On only my second cycle of charting temperatures, I got pregnant without any intervention. I know I ovulated on day #43 of my cycle and, although I was skeptical I thought I might be pregnant after 18 days of high-temperatures post-ovulation. I'm currently 8 weeks pregnant and still amazed that simple temping/charting worked.
If you choose to go the fertility treatment route, I would make one recommendation. Ask your OB/GYN for a referral to a fertility specialist or a reproductive endocrinologist. While your doctor is equipped to handle fertility issues, you will want to see a specialist who deals with these sorts of things all the time. It's sort of like asking a GP to do your open heart surgery. Sure, they could do it but it isn't their specialty. Also, a qualified and ethical fertility specialist will listen to your concerns about multiples and be truthful with you about the chances of having them. During the fertility treatment process, you will DEFINITELY know how many primary follicles (eventual ova) will be surging/dominating and can make your decision to fertilize based upon the data you see on the ultrasound screen. You will know whether or not there is a single egg or multiple eggs and you can decide how to progress at that point.
Good luck to you.