Man, I'm totally confused with my PS3.

I've got a network at home with one laptop and one Desktop computer, along with my PDA all connected. I recently set my PS3 for internet wireless connection which runs fine.

I decided to plug a hard drive into my Wireless router and have been using it for about two weeks now, with my computers. There are about 15gb of music on there and I want my PS3 to be able to stream the music, but it wont find the media server? The hard drive is actually a wee 40gb iPod which I just plugged into the USB port of my wireless. Is there something I'm doing wrong? Should I buy a proper network drive?, and if I do, how should I set it up? Sorry for all the questions, but I'm a bit of a tech freak but without the knowledge..... Any help would be GREATLY appreciated.

Cheers.