I read DC comics regularly back in the early 2000s but stopped for a while (budget). I'm trying to get back, largely because of your Batgirl, but the new 52 thing has me confused. Are there any good primers out there for people who haven't read much since

I wouldn’t say that there are primers, per se (also, WELCOME BACK!). However, that is the upside of the relaunch, you can start with a single tpb and be almost completely caught up on a title. If you get Demon Knights, volume one, you get a complete story and all the set-up and info you need to enjoy the ongoing book. That’s a big benefit, I think. You’re not far behind at all!