How do i connect to a vpn behind a double dhcp

I am trying to connect to a computer behind a 192.168.1.0 router. However, the router is located in a building that has a 10.10.0.0 and a static static public IP assigned to the building.

So it looks like this

Public IP: 209.248.161.0

DHCP: 10.10.5.0

DHCP: 192.168.1.1 (My router)

Computer:192.168.1.105

Any assistance would be greatly appreciated :-)