You should be eating some form of protein with every meal.

You should break up your eating times into 5 or 6 meals a day.

You should be working out your lower body about 50% of the time, focusing on squats for raw power.

You should go to the diet sections here and spend a few hours reading so you can learn how to change your diet. It doesn't have to be expensive. for example, I buy bulk rolled oats and have that for breakfast, as one of the things I eat in the early morn.

Having been in the army myself, the gentleman above me that said you are going to run your ass off is right. I would't dwell on the bulk thing for now... concentrate on your lower body, and make sure your legs are like iron, and you will begin to notice the rest of your body beginning to follow.

Good luck in the army!