Confused about my Calorie and Protein intake

IronDetermination

In pretty good shape except for some excess belly flab and looking to attack it before it is harder to get rid of! Started P90X and am on Day 3. I am confused about my calorie intake. Should I be on a low calorie diet in order to lose weight or a higher calorie diet because I am working out so much. I used the calculator here and it said I need 1200 calories and only 45 grams of protein daily. I was under the impression I should increase my protein to lose weight and build muscle. I am so confused. Please help.