No need for that. It's the basic function of Apple TV 1 to be set up with a computer (it has to be synched, you can choose to sync automatically or select some stuff, but the streaming stays active, anyway...). Without synching, there's no streaming. That's the first step. Sounds to me like you haven't really set up the Apple TV yet. Does it turn up on your "Devices" list in iTunes on the left? (The black Apple TV 2 doesn't do that, the aluminum version 1 does.)
Mac user since 1987. Running Mac OS X 10.8 Mountain Lion on a MacBook Air 11" & an iMac 27" and whatever's newest for my iPhone 4s, iPad 3 and AppleTV 2.
Apple Certified System Administrator 10.6, Apple Sales Professional 2008-2011, Apple Certified Mac Technician.