Small changes are best in my opinion. You take too much on at once and you will get discouraged. How about trying to incorporate a small salad with your dinner everyday? If you have a sandwich for lunch, put more lettuce in it and/or substitute white for whole wheat. After a week or two of meal adjustments, add exercise 3 times a week. Make sure there is a day in between each day you exercise so you give yourself time to get used to the routine. Set a goal of 30 mins if you think you're really out of shape and work as long as you can toward the 30 mins doing Walk Away The Pounds tapes or whatever you want to do...
Once you've made healthy choices or healthier versions of what you like to eat now, you'll find it easier to stick with it. Use the time now to figure out what you like and what you don't like. That way you have a range of foods you can try in the weeks to come...
GOOD LUCK!