Home network tips for newbie

Ladies and gents,

I've been without cable and internet access for several months now, the wife and I do all our surfing via smartphones, it has become very tiresome. On Monday I get wired back into the information super highway grid we all refer to as the internet.
I run my laptop wirelessly and my 360 stays wired in 24/7. I have a Linksys modem and a Linksys (Cisco) wireless router. I also run a free version of AVG anti-virus and malwarebytes on my laptop.

I was hoping some of yall could give me a few tips to stay protected with little effort.
Also what are some things I should install right off the bat?
How can I make sure my computer isn't already infected?
How to best protect from future problems?


Thanks