You need to configure Port forwarding and dig deep into the concept of
Reverse ssh to get it work. Additionally you also need access of your LAN router to configure port forwarding. Bcz what undergoes is when you access internet through a PC which is configured with a Private IP (local LAN IP), it uses tunneling concept to get access to the internet through one common Public IP, but to get access from internet to your PC you need to establish Reverse tunneling, which in turn, uses Port Forwarding feature.
An easy way could be (only if VPN connection is available), if you have access to your office intranet in which the PC you want is present, so you can logon to the VPN network and access the PC.