Important Info

I am 16, am 5' 11' , weigh 135, and bench 170. I have an very low body fat % and want to keep it that way. However i want to gain muscle tone and strength. I lift weights intensely for 2 hours, four days a week. I do high intensity cardio on the off days, and very light cardio on sunday which i consider my day off. I have a high protein, low fat,low carb drink after every time i workout. i was just wondering if how many calories i should consume to gain lean muscle mass, strength, and a little bit of weight. thanks for your help