I would also recommend trying to find at least a trial version of ewido, you can use it free for 14 days I think, then just uninstall it and reinstall if you want to use it again. It works really well when used in conjunction with AVG. The two programs tend to compliment each other and pick up problems the other missed.
Also use Spybot along with Ad-Aware. Again, they act as complimentary spyware and adware seekers that together will pretty much find everything on your computer. Let us know how it goes and if you need any tips on getting those programs to work!