Is AVG installed on your computer right now? I recommend downloading (from other computer) and using AVG Rescue CD which is able to scan your computer in the "offline mode". What is the situation after using AVG Rescue CD?
You may also try to install AVG on infected computer once your internet connection is available.
I have the Win 7 Defender "virus" on my laptop and I cant get out to the internet to download AVG. How can I use AVG to get rid of Win 7 Defender?