Something to look forward to - a new recording space you can do what you want with!
The SM58 is a good, well-liked stage microphone, less than ideal for instrument recording, especially for acoustic guitar, because it lacks the high end 'air'. Certainly use it, when you get the opportunity, but at the same time start thinking about improving your recording equipment to improvve quality. Great playing on your exisiting recordings, just need to capture the sound better.
Consider getting 1 or 2 GLS ES57 mics if budget is a concern - $30 each at Amazon:
http://www.amazon.com/GLS-Audio-Instrum ... microphone
They are a little 'hotter' than Shure SM57's and have a little more high end to them, too. For the price you can't beat them for instrument and amp miking.
Generally using a couple of pencil condensor mics is one of the preferred methods for recording acoustic guitar (there are a number of possible mic placements), but if your reocrding space is not acoustically treated (bass traps, diffusors,etc) dynamic mics will probably give a better result as they pick up less of the 'room' sound.
