VNC over Internet

[Rafeeq Manamal]

Dear Sir,
I have a LAN at my office which connects to internet through a CISCO
firewall system with ip address 213.132.33.14 <http://213.132.33.14> I want
to connect to a system in the same LAN with IP address
192.168.1.15<http://192.168.1.15>from my home through internet. None
of my LAN systems are connected directly
to internet. They are connecting through the internet connection sharing of
firewall system. Please help me
 Rafeeq Manamal