If you pay for your antivirusprogram get Kaspersky or some program based on kaspersky and/or even more antivirusengines.
If you want to get a free one your best bet is probably Avira Antivir. AVG don't found as many viruses, not avast either.

For firewall if you are skilled enough try jetico or maybe outpost. Comodo firewall is much easier to use and very nice, I installed it on my sisters machine, an old alternativ I used earlier was tiny personal firewall, but it's not developed longer and comodo is probably just as good. These firewalls are all free alternatives.
For a hardware based solution which you don't buy but instead run on an old PC or something check of m0n0wall or pf-sense, both FreeBSD based but the first one is slim, "simple" and don't require much resources and the later one is loaded.

For antispywareremoval try superantispyware, it finds plenty of spyware but the free version don't contain any real time protection so it's not as secure as the paid version, still nice for occasional scanning.

For cleaning, tuning and fixing your PC look for ccleaner which is free but rather limited and TuneUp Utilities which is commercial.

A very nice bootable CD with lots of tools is Hirens Boot CD but I really doubt it's legal/payed for content, I don't know for sure thought.

That should do it