Ok well in all honesty, if you are serious about gaining muscle weight, you need to do 2 things:
- Lift weights.. A LOT. 3-4 times a week concentrating on certain muscle groups each time you train.
- Increase your daily calories so that your body has enough to build the muscles with. As an example, when i was bulking up I went from 170lb to 185lb in just over 3 months. My body fat % stayed under 12% (was at 8% at the start) but you arent going to get more muscle without putting on a little bit of fat. I was eating close to 4000 calories a day which included over 200g of protein.