New VPN setup

[mkirros]

We're preparing to set up a VPN to allow remote access for employees who work either at home or at remote offices. Our network setup is:

Win2000 Server PDC which is the only server on the network. It serves as the DNS and WINS server.
ActionTec DSL modem/router which serves as the Internet Gateway and DHCP server.
Currently all IP addresses are internal, in the 192.168.x.x range, with the PDC and router having static addresses and all other addresses assigned through DHCP.
We have been assigned a block of public IP addresses by our ISP.
I want to set up a VPN using Win2000 RRAS.

My questions are:
Should I have two IP addresses for the PDC, an internal network address and a public address?
Can I continue to use DHCP for assigning IP addresses on the network? If so, can I continue to use the router as the DHCP server, or should I make the PDC into the DHCP server?
Can I continue to use private IP addresses in the 192.168.x.x range for the network computers? How about for the remote access computers?

Sorry if any of this is naive, but it's my first shot at setting up a VPN. Thanks for any help that you can give.