Why did you pay him??!!
Sorry there is not much you can do. Never trust obscure download links and always run things through multiple anti-virus programs.
More than likely you still have the key logging program on your computer. Defiantly get rid of it as soon as possible.
If you looking for free antivirus / anti malware I wougld highly recommend you use the top 4 from this list: Anti-Malware & App Launchers - The Best Free Software of 2012 | PCMag.com
As for game boosting programs I used Game Booster 3 (made by IObit) for several years on my laptop.
Game booster temporary closes unneeded processes running on your computer while in gaming mode. When your done playing just return to normal mode.