First off, Congrats on wanthing this wonderful tool to help you get healthy!
As for your situation, I might not be the best person to help but here is how I see it. I was told in my seminar by the doctor that would be doing my surgery that he prefers you NOT to get pregnant for at least ONE YEAR. So as long as you are sure you are wanting to wait a whole year I say go for it. Get the surgery done so that your body can be used to the lifestyle change and allow you to lose some weight before gaining weight for the pregnancy. This way you wont have as much to lose to get back to being healthy! Make sense?
Good luck!