Branch office logging into Active Directory

I have a question that is stumping me and I know that it should be possible to do, but I just have not been able to find the answer as of yet. I am in the process of opening up a branch office in Canada with 2 people and a printer. What I want to do is to allow them a VPN connection to my office here in London. What I want to do is to allow the staff to login to my domain here, and allow myself access to the printer in their office.

Im not sure if it is router issue or if it is something that I need to do in AD to allow this, but they will not have their own DC.

Thanks