Actually I sorta got into this postion by accident. I used to work in accounting, but spent alot of my free time working with computers and learning about them. When I first started working where I work now, I was in an accounting, clerical-type job, but started helping out with various PC problems, and demonstrating my abilities to both use, and fix PC's. When the IT guy left 6 months after I started the powers that be figured it was cheaper to simply move me over there and spend a little money on some network admin training than it would be to go on a full-fledged IT candidate search. That was about 6 years ago and I've been here ever since.
Definitely just a case of being in the right place at the right time. 🙂
So, unfortunately, I don't have any actual job-hunting advice for you, other than if you really want the autonamy that goes with being the whole department, focus on small companies, and accept that you will probably not have much authority in your job. The people with authority are all in management postions, there's no one for you to manage when you're the one-man IT Department! [Life of a one-man IT department]