Question .... I am currently using a Netgear Wireless Router (bought about 6 months ago) as my main firewall and had disabled Windows Firewall .. was that a big mistake?

A hardware firewall is better at blocking inbound threats then a software firewall is, but it does not block outbound threats, if you would like a both way software firewall protection, a good one to try would be Zonealarm, there is a free and paid version of it. :wink:
Also it will work fine along side your hardware firewall.

Is there a recommended Antivirus software? I noticed Eddy's website had AVG or Avast.

Well you are on the Avast anti-virus forums :), so we would all suggest Avast (there is a free and paid version).
But its up to you if you swap it with Nortan, some people like Avast more then Norton, some don’t, it all comes down to personal preferences.

have a good day now

–lee