Probot, as Jokerr31 mentioned earlier, there ARE girls out there that would beat your door down. Working with disabled kids speaks VOLUMES about you as a person, all in one sentence. There are lots of girls out there that would go for you. What you need to do is internalize the fact that you are the prize, not her.
I'd be willing to bet that when you're in casual conversation with a woman (any woman), and it comes out that you work with disabled children, their faces light up. No doubt they're thinking "what a great guy". It's an advantage, don't be afraid to use it, and I'm sure you'd never overuse it.
The best piece of advice I've seen given is to read the DJ Bible. Then, read it again. Apply what you read. Then, apply it again. What I'm getting at here is that you've had a long time to get set in your way of thinking about women. Time for a change. It works.
I'm older as well, have two kids. Wife has been sleeping on the couch for eight years (you can guess the rest) - I gave her dissolution paperwork Friday. Not too far removed from the person Nighthawk spoke of. What I'm getting at is that I was out of touch, and this site opened my eyes bigtime. I now have two girls essentially waiting for my dissolution to become final. I never thought someone in my position could attract.