I second most eveything Belexes said. the Church Audio mic is a great deal for the money and will be a huge improvement over that mediocre Sony mic.
I'll add one thing to what he said, though. You may want a Church Audio preamp even if you tape extremely loud shows. That is because there has been lot's of talk that at loud shows the Microtrack will sometimes distort even with the MicroTrack's levels turned down a low as possible. I don't know the technical terms, but you can't reduce the incoming signal all the way down to 0 with the Microtack & sometimes even the minimum level can be too loud for the Microtrack's preamp. Since the Church Audio ST-9100 attenuates as well as amplifies, you probably can avoid this problem by running an ST-9100 into the Microtrack's line in and using it to attenuate rather than amplify the incoming signal. If you also tape quiet shows, this would be a particularly good option because the Church audio mic is farily insensitive and you may find you need to use the ST-9100 to get adequate gain for quiet shows.
If you only tape loud shows, maybe you don't need the preamp though. Very possibly the Church Audio mic wouldn't overload the MicroTrack's preamp since it is so insensitive and if it did, maybe all you'd need is to buy the 10 DB attenuator from M-Audio to avoid the problem. I would feel safer going line in with the ST-9100 myself however.
Maybe someone who uses a Church Audio mic with a MicroTrack can chime in on this. Very possibly the problems with the Microtrack's preamp overloading involved mics far more sensitive than the Church Audio. Actually Chris Church would be the best one to tell you the best way to use his mic with a Microtrack. If he doesn't see this and respond, you could send him a PM. He's very good about answering questions.