W2K VPN with 1 NIC and behind FW

I have a small test network with a W2K Domain controller behind a Linksys router. I was able to setup the VPN on it and have Linksys router forward its private I address to a public one. So I can VPN into the domain controller, but I cannnot get into the other clients. It won’t allow me to even ping them.

Is this becase I need 2 NIC? If I do can both of the NIC’s be on the same subnet? Can I keep just 1 NIC and change other settings?

When I VPN and do a IPCONFIG /ALL I see a 169. IP, soit is not the same as my network which is 172.16.x.x