I use AVG too but sometimes bad stuff gets through before they have a clue and an update. With these types of virus' even if you paid for the fix from the warning notice, you would not get a fix. I had this happen once to my computer but as soon as I realized I had the virus, which was spread by the warning notice that I had a virus, I shut my computer down. I went to DH's computer and researched the virus and found a guru site that gave the instructions to remove the virus. I turned my computer on, downloaded the needed free software and made the fix myself. I used Malware Bytes which is a free download.
The computer place should be able to get in and back up all your important files for you. Then they can clean your hard drive and reload your system files, AVG, Open Office etc. You should be good as new when they are finished. Good Luck!