Remote Access Between 2 networks

Hello,

I have a computer thats in a business running Windows 2k. One of our vendors needs to access it remotley to do upgrades or fix errors within the software. The software they required us to use is Symantec's Pc Anywhere.

The Problem:

We are running two different networks within the business.

Network A is for daily operations (7 computers are on this one), with only one computer having internet access (We want to keep it this way for many purposes). This network is all connected to a Linksys hub.

Network B has 3 computers (one of the computers is from network A), that all share a DSL line, and go through a netgear FVS318 Prosafe VPN Firewall.

The computer that is connected to networks a and b can access the internet, but no body can access it from outside the building (WHAT SECURITY! LOL!).

Is there something that has to be setup within network b's router that I am missing?

Any help is appreciated.

DON