Eat more... Basically... Drop the weight gainer cause 10-to-1 that's all simple carbs, and u don't need those... i'm guessing u work out in the evenings, so try this:
early mornings: take a whey protein shake and some complex carbs (whole wheat bread with apple sirup or something, yoghurt with muesli does the trick too)
eat every two hours during the day
moderate warm meal
have a whey shake with some dextrose sugar (30 gr. whey, 60 gr dextrose) an hour before u work out
after ur workout have some yoghurt with muesli again
have a whey shake before bed
in total u should be having about 9 (!!!) meals a day, for a total of 3800 kcal a day, 55% carbs, 30% protein and 15% fat...
check out
www.bodybuilding.com for more indepth stuff, click supersite, and well, u'll figure out the rest... this got me up from being 63 kg (140 punds) at 18% to 170 at 9% in two years time...