Thanks for your reply,
I actually e-mailed Grisoft and asked about their AVG. They e-mailed me back saying that I could not use it for free but could purchase their professional edition for $39.00. I then found a link at about.com that said that AVG does offer the professional to non-profits and school for free. They have a form that needs to be faxed with the request for a "discount". I would need to fax it to the Czech Republic which would probably cost me as much as purchasing a low cost AV program.
After I read your post I contacted Bit Defender and they replied that I could use it their free program at the school for 1 year. I am not sure what happens after the 1st year but I will take it for now. Thanks again for your tip. I can now surf safely at school.