Remote Desktop Web Connection (Vista) Network Problems

I am unfamiliar with how to access my work computer from my laptop with Remote Desktop Web Connection. When I plug the laptop into the internet at my office it works, however it doesnt work when i try from a different location. I am running Vista on both machines.

The posts mention enabling ports on routers etc. but i am very confused and would appreciate specific instructions on what could be preventing me from accessing my work computer from my laptop. I have gone through tech support with windows but the problem seems to be my network and that is where i get confused.

Please Help

Thanks