It's not the mass air flow sensor that's gone, it's the oxygen sensor, the first one in the exhaust pipe. You should be able to see it screwed into the exhaust manifold, in front of the engine, with wires coming out of it. The sensor itself would probably cost around $125-$150 from the dealership, but you can most likely pick one up from Autozone for cheaper.
But if you're only at 79xxx miles, you're still under the emissions warranty and this repair shouldn't cost you a dime. Go to your local dealer, tell them you have a bad first oxygen sensor, and that it should be covered under the 8yr/80k mile emissions warranty. Should be completely free. But if not...
I'm not exactly sure what's involved with replacing that sensor on that motor. I don't know if you have to remove the heat shield or whatever. But once you get to it, with the right size socket/wrench (if using a socket you need a special o2 sensor socket), it'll come out but it'll probably take quite a bit of force. Basically just unplug the sensor, unscrew it from the exhaust, screw the new one in, and plug it in. It's just getting to the sensor and breaking it loose that are the problems. If you're comfortable working on your car and have the right tools it's not difficult. If not, any mechanic or muffler shop should be able to swap it out for not too much money.
2003 Spec V
Crashed, abused, loved. Damn thing just won't give up.