How do I browse and save files from a remote computer via VPN?

[Excitable Boy]

I'd like to be able to occasionally grab a PDF or Excel doc from our server at work with my Moto Droid. I've got the VPN to connect, but am not sure what to do next? I've tried to browse files using Astro, but don't seem to see the server listed. The computer I'm trying to connect to is running Windows Server 2003.

Any ideas?