it's not free, but
f-prot is a very good AV for the price (~$30 US). It does offer a 30-day free trial if you want to give it a test run. I should also mention that f-prot is free for Linux users (at home).
as for a firewall, I'd highly recommend
sygate, although I'd much rather see you use a hardware firewall or something like
smoothwall
There is also
Clamwin (or
CalmAV for Linux), which is free, but only for advanced users imho. Despite being a bit less noob friendly, ClamAV/Calmwin are the the best AV scanners I have ever seen, period.