Katie, why don't you start with something simple and reasonably priced ? you must have at least some basic computer skills so have a peak at MotePC.
It was here when we purchased late in 2004 and we did an update in 2005. A few months back I purchased this latest version from them. I too researched many options of software but I just wanted my own disc and not to have all the ongoing fees and pay for updates ect. So I stayed with this MotelPC system. It's $299 for online download or as I did $320 for your disc. Also for I think $1100 there is a more comprehensive system from them with channel managers and other upgrade features. I do not have a booking button and I do not use a channel manager but still work OK with all the Wotif OTA's as well as Booking.com