Centos 5.7 not included in rpm library

I'm running Centos 5.7 and am getting errors about clamav being outdated. Local version is .97.2 and recommended is .97.3, when I run yum update I'm getting no updates. I checked the folder http://software.virtualmin.com/centos/6.0/x86_64/ and clamav is up to .97.13! When I check the folder list in http://software.virtualmin.com/centos/ there is no folder for 5.7 so any users who cannot update to centos 6, because we're renting servers and don't have the ability to reload it from scratch from a CD need to still be kept up to date. I note there is a 5.6 folder but that only has .97.2 version. You could just put it into the bleed folder as there is a 5.7 bleed yum depository but I wonder how many centos 5.7 users use that?

As more and more virus and attacks hit the server, surely keeping clamav up to date is an essential part of the virtualmin pro software I purchased?

Please let me know how I can proceed. Best Wishes Mark