Searched, far too mucf stuff to pinpoint what I need

Okay, I have Audacity. I am going to get a Shure SM57 (I hear they are good and versatile).
I am simply looking to make decent recordings of songs- guitar parts. As in, demoing the whole song in guitar form- with overdubs etc so it would sound like JUST the guitar to show the rest of the band.

What else do I need? I hear about compressors, pre-amps etc but have NO idea what any of that stuff does- is record and go not enough.

Thanks. Sorry if this is such a n00b topic, but I'm on a limited budget, and there's so much info out there that I don't know where to start!
preamp if im not mistaken helps the sound quality going into the computer. as for compressors, they make the signal more sensitive (picks up more). correct me anyone if im wrong.
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Ahh I see. And are these pre-amps expensive?? I'm looking for cheap but lasting/usable equipment, so I'm gueesing there's alot of stuff out there to go through...
you will need an interface
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Such as?? Is Audacity not enough for simple stuff? I'vr used it before and it seems fine to me for simple song structuring
Two things to consider. Use a mixer between mic and PC. This will allow you a bit of EQ which is best done externally. Audacity can do a lot of Effects but post production. i.e. you apply the effect after you have recorded so you don't hear the result as you play. I use a simple mixer with effects built in to let me hear the result as I play.
The other problem is latency in your sound system. This causes subsequent tracks to record a bit behind the original. Its easy enough to re-align the wave but its best to be aware of it. It doesn't affect what you hear as you record it.
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I hear about pre-amps. Whats a good, inexpensive pre-amp??

And I'd only be looking to record a track at a time, so I don't think a mixer is a necessity?
You can only record multiple tracks with mixer if it has preamps, those usually cost up in the $1000s. You could get a cheep interface or a cheap mixer, though I believe that interfaces with good preamps have better sound quality.