Apple TV and media sharing

Long time reader, first time poster.

So, here is my dilemma. I recently purchased a Timecapsule to serve as my home server. I have an older MacBook running Tiger OS that I want to use as my home media server. Here is a list of the hardware I have in the house:
1. MacBook running Tiger OS
2. 750GB external harddrive connected to the MacBook
3. 2TB Time Capsule (MacBook is connected to the Timecapsule via ethernet cable)
4. MacBooc Pro running Snow Leopard
5. Sony Vaio running windows 7 (Primary work computer and travels with me and holds most of my data and media)
6. Wife's MacBook running Snow Leopard
7. 1st generation Apple TV with 160GB hard drive

What I would like to do:
As I travel with my Vaio and my MacBook Pro, I want to use my old MacBook as my full-time media server for the house. I have iTunes installed and am using the 750GB external drive to host the media for the MacBook. I plan to link this computer to my apple TV. Ideally, I would like to be able to back up the media from my Sony Vaio and the media from my wife's MacBook so all of our combined music and media will be available on our Apple TV. (We use the Apple TV primarily to distribute audio throughout the house utilizing the "Remote" AP on our iPhones.)

I have turned on all of the "File Shring" protocols on my Media Server (The MacBook running Tiger) and I can see the internal hard drive from all of the other computers when I share, but I can't see the attached external hard drive. Does anyone know how to make it so I can view the external hard drive attached to the MacBook from other computers? I plan on backing up our music from all of our computers to this external hard drive so the apple TV can play all of our music. If this is not possible, can Apple TV utilize the "Sharing" on iTunes so we can see all of our combined music?

Thanks in advance for your suggestions.