You might explore VPN "Virtual Private Network". This usually involves having a router at client software to connect to the server. It might also involve two rounter at each end to connect two separate networks. There a a lot of different way to do it. Once the routers connecte, the remote location would appear a locale nodes in the network.
There are a ton of ways to create VPN/s both using software only as well as hardware. I havn't used a VPN before, but if I needed one, I would be inclined to go with a hardware solution as opposed to a software only solution.
You would probably want a high speed connection between the two remote and locale computers like cable modem or DSL.