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.
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Game booster temporary closes unneeded processes running on your computer while in gaming mode. When your done playing just return to normal mode.