Well done. Perhaps you can mark this thread as solved. The AVG/SAS thing was a red herring. Do try now to think what could have happened to bring this malware attack about.
I prefer to pay for McAfee and if I am going to pay, I'd rather pay them than AVG or the other small suppliers who may not have the resources to maintain and update encyclopaedias etc. I'm pleased with Ad-Aware - I keep Ad-Watch live and it detects and blocks the odd attempt to connect to a site in its database of baddies.