Linksys VPN networking issues

I'm looking for an answer to a problem I can't seem to solve. I have a small business with DSL piped in to a Netopia router (which is passing everything). This router is plugged in to a Linksys VPN router which is then plugged in to my internal network and providing DHCP addresses to the network. I'm looking for two things: first, I need users to be able to VPN in to the Linksys router (and therefore the network) and second, I need to have a remote location (also with DSL) VPN in to the main office and replicate servers in a wide area network of sorts. I know the remote location server should be a DC with a global catalog, but without the VPN connection, it won't replicate. How can I solve both problems?