Pcanywhere

I have a dsl router at my office and a cable modem at home and want to establish a remote connection between the two using pcanywhere. However, the cisco 676 router is stopping me from making the connection. I know how to change the ports pcanywhereis using. That isn’t the problem. The problem is all the workstations here at the office have non-routable IP addresses and I obviously can’t expect to connect to a non-routable IP from home. My home computer can’t see my office computer. The only routable address I have is the one for my router. How do I make my home computer connect to my router using pcanywhere and then connect to my office workstation? Please don’t give a brief answer. I need specifics and a very detailed answer.