I don't have hands on with your amp - so I can't speculate on what your sound will be.
I use a POD 2.0 (and a Johnson J-Station) all the time. I get very good sounds. A couple guitarists I respect (both for their chops & their sound) have commented on how "real" my guitar tracks sound. As important, both tried the POD and thought the emulations were very good (neither of these guys owns an emulator - simply because that have several great amps and nice rooms to record in.
I do a lot of recording late at night - and the POD (or J-Station) allows me to put down guitar tracks while people sleep - I could never do that with a mic'd cabinet. That alone, makes the POD a logical choice - for me.
That being said, if you feel you get the tones you want from your amp - and you can crank up and record whenever you need to - a POD may be redundant. In which case, it make make more sense to buy a 57 and spend what you would spend on a POD (abourt $250???) on a low cost condensor mic - (for vocals).
However, buying a single 57 may be all you need for now. It is a very good mic for an amp cab and it can work as a vocal mic (for the right voice). I've always thought a 57 works best with a "screaming rock & roll voice".