Go back in to the Server Console and select option 2, Configure this server. The first two things to change are the domain and hostname. Skip past the rest. You will have to reboot the system at the end.
That being said, I'm not sure that using DNS will necessarily resolve the issue. It might be better to temporarily setup a VPN to connect the two sites. Other than that, I suppose that you could do some port forwarding, but that seems like a bad idea.