Ethernet shield Coding

Finally i made i work webserver.
2nd question over here is how to access over internet.?

I have connection setup like below
I have network switch 5 port.

LAN NETWORK connected to server to switch. port 0
PC Ethernet port goes to same network switch, port 1
Ethernet shield from arduino connected to network port 2

all networks are on same hub. Let me know How to configure for Below setup . I am using Windows XP operation system.