Before I get to the question of the pop-ups, I'll deal with the approaching expiry of your security software first.
There are 3 key elements to providing complete a complete security solution for your PC. First, you need a firewall. Zone Alarm Free Edition is the most popular solution, although some people prefer Comodo. Then you need anti-virus software. AVG Free is the most popular but some people prefer Avast. Lastly, you need an anti-spyware program. AdAware and Spybot are the most popular. (You should only have just one firewall running and just one anti-virus program, but you can have as many anti-spyware programs as you like).
Links to all of those programs are here:
http://www.theanswerbank.co.uk/Technology/Ques tion380467.html
Download the programs you require, then uninstall your existing (commercial) version of AVG and install your new software.
Now for those pop-ups. There are dozens (or possibly hundreds) of programs which claim that they can eliminate pop-ups but the simplest solution is just to use a decent browser. Most of the 'regulars' here in AB's Technology section, have switched from Internet Explorer to Firefox. It's faster, more flexible, better designed, more secure and (importantly from your point of view) it's built-in pop-up blocker actually works:
http://www.mozilla.com/firefox/
Chris