Hey, don't despair!
You know that it will take you some months to lose the weight you want to lose, right? So you'll need to take the long view. Suppose you lost a pound a week--how many weeks would it take? Make that a sort of target date (not that you HAVE to hit it exactly--it just gives you something to aim for). Then break down the time into smaller goals. Not just weight goals, but also eating and exercise goals.
Any number of websites can give you guidance about goals--I use FitDay, as do a lot of folks here. It allows you to track your foods and it does all the adding for you.
As for exercise, try to do something active almost every day. It doesn't have to be some big athletic challenge! If you have FitTV in your TV package, check out some of the 1/2 hour workouts. They are enough to get you started.
Don't give up. You aren't doomed to fail unless you believe you are!
Jay