This is the place to start learning about configuring a VPN in a Windows networking environment. What you want is a "site to site" VPN.
Don't expect it to be easy to figure out, don't be too surprised if you don't get a huge amount of help here, and, given that using RRAS on Windows Home Server isn't supported, don't be too surprised if you can't really get it to work.
I'm not on the WHS team, I just post a lot. :)