You could split the backups to multiple files which would make smaller files. Although it does take a while, you can also zip the files which will give you about 80% compression. Be advised that the normal zip tools in windows won't handle files that big. You might want to try 7Zip or spend 60 bucks on WinZip Pro both of which come with command line versions.
--Jeff Moden
Change is inevitable... Change for the better is not.