What Jennifer said makes perfect sense, plus I'd also look into Brain Wave Entrainment.
Transparent Corporation iMusic by Volition Thought House: The Ultimate Brain Enhancer | Volition Thought House
I have ADHD and have been using both systems. I've only recently started using neuroprogrammer 2 (np2), but have used iMusic for months now and it's helped noticeably cognitively speaking.
If you wish to try Imusic for free and yet own the whole collection (although it's the former collection, but it does the VERY same thing as the new collection) go to :
imusic | isoHunt - the BitTorrent and P2P search engine and get the link with 5.62 G