Hi,
A good multivitamin would help you out. If you have extra money, BCAA's are really good to improve recovery. Something like excell, and Xtend are really good products. Don't be fooled by those NO products, as even though you might get good pumps, I do not beleive that solid gains will come with it.
You did not stated how long you have been training, but I will mention it anyways. X Factor is an extremely good product, and will help you to gain size. I did 3 cycles of it, and will continue to do so as it's very effective, and worth every penny.
Good luck.