Actually there are different kinds of protein powders. ^
There's slow and fast release protein. For a quick guide on what they are: http://www.bodybuilding.com/fun/md99.htm
Also like the previous person posted, don't rely on protein from powder alone. Make sure you eat lots of high protein foods (chicken breast, turkey breast, tuna, other lean meats, kidney beans etc)
It would also be a good idea to take out simple carbs out of your diet, more details here: http://www.fitday.com/fitness-articles/nutrition/carbs/simple-vs-complex-carbohydrates.html#b