This can be done with OpenVPN.
If i understand correctly:
you have a remote location that you want to connect as a openvpn-client to an openvpn-server and then connect to a web server on the client over the VPN ?
This explains HOWTO:
HOWTO: Expanding the scope of the VPN to include additional machines
For the sake of your sanity, why not setup your OpenVPN server in your office where you are and take the service provider out of the equation. At least for testing ...