well the rep ranges you are doing right now WILL build strength, and yes the carbs definitly help. You should increase the weights when you are no longer hitting failure or near failure by your last set. This also means until you feel completly strong with a certain weight, do 1-2 sets with your starting weight so you are warmed up, then try to go up a little for the next few sets until you are reaching failure, if you get to the end of you sets using the heavier weight great, if you are feeling weaker, drop the weight back down. An example would be

Military Presses (you currently do 40lbs), if you are doing 6 sets
40 x 4
40 x 4
50 x 4
50 x 4
50 x 4
40 x 4