For lunch, you could bring a couple of chicken breasts and get a salad from the school (no dressing though, just get your greens, carrots, and eggs on there). Chicken breasts are easy to cook, and don't take much time. If you don't already, you can get interested in cooking techniques. It honestly only takes about 10-15 minutes to cook a package of chicken breast. Cook it at night; take it with you in the morning.
As for dinner, just tell your parents you want sirloin steak, and you want it now damnit!
Top sirloin is perhaps the most protein-dense cut of meat around, with around 80-90 grams, depending on method of cooking, for a 10 oz cut. It also has the least amount of fat and sodium out of all the red meat cuts.
Chicken breast, sirloin, and fish, all the time. I understand you pretty much have to eat what your parents fix for dinner, and that's fine. You're not going to hurt too bad if mom cooks meat loaf or chicken fried steak for dinner. You're 15-16 years old; your testosterone levels are roaring, and that's a huge advantage that you have over a 28 year old man who is trying to achieve the same goals as you are.
Don't become worried about putting fat on. I wouldn't increase your cardio levels. In fact, my cardio sessions are never more than 25 minutes! HIIT (high intensity interval training) is perfect for somebody looking to build lean muscle mass while keeping fat levels low. Running 3 miles a day is only going to put your body in a catabolic state because you're using up so much energy from your carbs that your body will look to your protein levels for energy. Cutting into your protein levels during cardio only makes your muscle building process that much slower. My personal opinion, don't do long distance training. It will only negate all the hard work you put into consuming a lot of protein.