Best thing for you would be Optimum Nutrition's 100% Whey (Double Rich Chocolate is like drinking chocolate milk VERY good)
You can get a 5 lb tub for about 30 bucks, and it has 80 serving.
29 gram scoops, 23 grams protein, 3 carbs.
Take 3 times a day and you'll be set.
(On a side note, since you are supplementing with protein you wont lose *bodyweight* since you will be suppling your muscles with nutrients to grow BUT you WILL LOSE BODYFAT! So don't watch the scale just check the mirror OKIE?)