eat! eat! and Eat again. I doubt you have much problem finding the motivaiton workout, you do look great. But if you want more muscle you've got to eat. At your size, an average of 3500 cals a weekmaybe more...that means eating every 2-4 hours a day....everyday...all day....I may sound bitter? your right. I'm choking down my 3rd meal of the day right now. And I don't much feel like eating. really work your diet and you'll put on 20 pounds in a year I bet. good luck. that is if want more muscle.
Personally, i have to have alot of muscle to make my belly look small!