This page seems to have the info on how to set up the port forwarding on the D-Link router.

The issue I see is the fact that each ISP caches DNS information. This means that when I go to your website, I'll get the IP address from my ISP's DNS server, not yours. If you change the IP address on your domain name, it will take several hours to several days for the new IP address to propagate throughout the other DNS servers.