AppleTV Home sharing. Mac Mini? Airport w/ Time capsule?

Hello all,

Ok I've been searching around but can't seem to find the answer... Here's what I would like to do:

I would like to be able to turn on my AppleTV, scroll over to "Computers" and access my TV shows and movies via home sharing without having to turn on or open my macbook. The problem is the macbook has to be in the vicinity of the AppleTV in order to access the media so if it's at work or my wife wants to access the media when I'm not home it won't work. I want to always be able to access it.

Now that being said, I know there will need to be additional equipment involved in this process. I'm here looking for recommendations from the pros. Should I get a Mac Mini and import all of my files to iTunes on the Mac Mini and just leave it on all the time connected to wifi? Do I need an Airport with an external hard drive attached?

Thank you in advance for your help.