Connecting my stereo to my computer with WI-FI

My goal is to connect my new hard drive to my stereo so that I can play and listen to the 720 hours of music that is on the hard drive. I am trying to figure what else i need to purchase and how to set it up correctly.

I have a:
dell desktop computer
Dell Laptop computer - Inspiron 8600-equipted with wireless capability.
D-link DI-614 Router
just purchased WD 160 GB hard drive - MDL -1600B015
Stereo Receiver - Onkyo Model number TK-903 - The receiver is over 7 years old. The back of the receiver just has imputs for speakers and connectors for other stereo components like CD players, tape decks etc.

Thank you in advance for your guidance.

David