The complication here could be SSL related. SSL VPNs can work in several different ways, and some of those are designed for one-way connections - ie: accessing resources on a central host in a secure way.

It is very possible that the PC at your office will have no way of accessing the remote PC by connecting to the Windows file sharing port numbers. This will depend on how the SSL VPN has been configured - I'm not completely familiar with the Cisco solution, but have worked extensively on the Juniper one which bears some similarities. Perhaps someone more experienced with this solution can comment on whether it is an easy configuration change to allow a more traditional tunnel to be set up to allow devices on the LAN side of the SSL host to connect to the initiating client?