How to setup a web server on network with wireless router and DSL cable!

I am newbie to networking. I would like to set up a Web Server on small home network that include 2 computers. I got followed components:
– one wireless router D-Link
– one laptop with wireless USB
– one computer that act the web server

I can configure the internet connection on home wireless network successfully. Now I want to setup a web server, but I am not sure how to configure in order to get the static IP address from dynamic IP of ISP. So anyone can access it from world wide web? Please help me the solution. I would appreciate it. Thanks in advance.