I agree with Adgal -
Don't focus on weight, focus on eating right: Cut out sweets, eat 5 small meals per day, avoid soda, drink plenty of water, increase fruits, vegetables, fiber. Avoid added salt.
Walk daily.
Enjoy!
Congrats on your pregnancy! Right now is not the time to worry too much about weight, especially not about losing it. Instead, as RmberMe said, focus on eating healthy...lean meants, fruits and veggies, lots of fiber and water. As far as I know there aren't a whole lot of extra risks associated with pregnancy while overweight. Blood pressure and gestational diabetes are the only ones that come to mind, and you will be monitored and tested for both.
If you already have an exercise regime, don't be afraid to continue although you do want to avoid heavy lifting, etc. as you get further along. Walks at a brisk pace are great, at a slower pace if you are not accustomed to exercise. Don't focus on weight, focus on being and staying as healthy as you can. Congrats again!!
I am worried about this too, I am 42 and overweight. I am on medication for high blood pressure already. I am 7w preg. I am trying not to eat what I shouldn't, but sometimes I am soooo hungry I just can't help myself :-( I think you can eat as much fruit and veg that you like, making sure you get red meat. And maybe have just one day a week where you can just have anything you like. Thats what I am trying to do. Good luck