connectingh via VPN

Can you explain a little further? You SHOULD be getting an additional IP once you establish the VPN connection, that's what gives you the access to your office network. Not sure exactly what the problem is. If you do an IPCONFIG /All, you should still have your original IP address and an additional IP handed to you by the VPN server.

Thats the whole point of VPN. When you connect via the VPN, you become isolated from your original network and connected to the office network. If you retained your original network connectivity, there would be no security for the office network. Your computer would act as a giant breach in security because it could route traffic from your public network to the private network without going through the office's firewall.