^ quite right 'rahnoo', what I should have eluded to (was trying to be a little non-technical) is an interface acts for the mic with eq/gain structure etc. which I would doubt a pc card would cater for adaquietly, and also xlr input with fewer (hopefully no) adaptors.
I would still maintain getting some sort of interface for a mic like a shure to make things simpler with connections and be more assured that the mic is then able to convey the spectrum of sound you want to record.
Mics and recording can obviously get VERY costly, but a simple enough setup has/is used often with not bad results.
With your setup 'as is' _tom_ you can try and utilise the v-amp etc. with all kinds of hookups (I am not too familiar with the v-amp) but may encounter some sound degridation or 'colouring' by going through it. An interface (in my understanding) is more a transparent bridge (often tweakable on the appliance) between the mic and the recording apparatus (in this case your laptop).
Many have used usb mics into their soundcard, but many on here have stated they are not best happy with results. All depends on what kind of quality you want or what you want to do with end result (recording).
A SM57 is pretty much an industry standard and well used mic. Phantom power as such is not necessary but getting a good signal path from mic to laptop is very much needed (or you may be wasting time,money and energy and become frustrated). An interface designed specifically for this purpose would help with all this and simplify matters. Also, they come with Phanom Power so allowing for other mics to be used if so desired at a later date.
I did quite alot of research myself and have ended up with a Shure dynamic and a Blue 'the ball' (both for little diversity and also to try dual mic'ing at some point).
I still would recommend, mic - interface - pc/with program.
