VPN configuration Questions

Hey, so im trying to set up a VPN network from my home computer to be accessed via public networks (work/coffee shops..)

anyways

1. Configured router to forward port (23434) to (1723) for access via VPN
2. Windows 7 Desktop (VPN server) made new Incomming connection for specific VPN user
3. On laptop wanting to access VPN
a) Created VPNhome using PUBLIC address (24.144.x.x) which does NOT connect
b) Created VPNtest using PRIVATE address (192.168.x.x) which DOES connect

just curious as to if I missed a step for the VPNhome to be able to connect THROUGH the public network


Thanks;

403Phaze