Prevention is better than cure. My set up is in my sig. You might choose to add a hosts file, and/or SpywareBlaster, by Javacool. Noscript is a very useful extension for the Firefox browser, and something to help monitor that all your software (Java, Adobe etc) is up to date.
MBAM is also a very good anti malware.
Basically what you have is quite adequate, it would be wise to just try and plug whatever holes remain.