In some cases, it may be possible to recover files which have been deleted by a virus. It is usually safer to restore them from backup (you do make backups, right?).
In terms of pushing an antivirus update, you'd need to have some sort of software that is able to control the remote PCs so that you can place the files on them. Many AV vendors now provide the technology to do this in their enterprise/corporate versions.
For more information on this topic, visit these other searchSecurity resources:
David Stom's Security Toolshed: GoToMyPC a nifty utility, but can skirt security measures
Best Web Links: Data Protection (Backup)
This was first published in January 2002