Protein, Carbs, Fats, Alcohol...they're ALL calories!
My man, you're going to have to do some cardio if you want to REALLY lean up your midsection.
You'll need to create an ever-so-slight deficiency in your caloric intake, make the deficiency come from your fat calories (but don't cut fat out completely) and up your cardio in frequency AND intensity.
Work your abs hard, but keep the rest of your body busy with resistance training as well. Remember, spot reduction is a MYTH! In order to lose fat in one area, you've got to work your entire body. Your body has it's own "order of fat loss", and there isn't much you can do about that...it's just genetics. For men, it's usually their tummys and love handles that go last. With women, it's their thighs and butts.
Also, with your body weight and activity level, you are doing fine with your current daily protein intake and won't really benefit from taking in any more per day.
Good luck and keep it up.