Spysweeper is a great program however I would not purchase it, I think you have all you need I use the same programs. If by some chanch you do get infected you can post a hijackthis log and thats free also!
A couple of other great free programs are A-squared and windows defender!
http://www.emsisoft.com/en/software/free/
https://www.microsoft.co.ke/athome/s...e/default.mspx