Hi again Ice - glad to see you're not giving up just because of some difficult choices. Just thought I'd throw my $2.00 in here (not necessarily more valuable, just usually long-winded, hehe) Your comment "One thing I don't get is how pretty much everyone seems to be using omnidirectional mics.. mine's unidirectional. Is that a problem? Unless there's something I'm missing, I like it because there's less pickup from anywhere but where I need it. " kind of threw me. I'm not sure where you heard that omni's were used mostly, but it is certainly NOT true for playing live. Your comment about pickup only where you need it is the clue. An omni mic will cause feedback on stage with a lot less volume than a directional mic will. Even in the studio, very few people tend to use omni's, except for room mics (ambience), again for reasons of sound control.
Your 57, depending on your vocal characteristics, should do fine for some time. As for your guitar, another mic could work instead of a pickup, IF you sit still on a stool and sing and play. For moving around at all, a pickup is a more consistent sound. If you can afford it, anything by Fishman should do a good job. Piezo type pickups tend to give a more natural acoustic sound on an
acoustic guitar than one of the magnetic type pickups do.
There are "acoustic" type amps available, that would probably work as an all-in-one solution for voice and guitar, but won't sound as good for voice as a real PA system. As tight as your budget is, it might take a while to save for something that won't make you sound like crap vocally.
The portastudio thing might make some sense if you're intending to do pre-recorded backing tracks to sing along with - another good reason for that piece of gear is self-critique for purposes of improvement. There is nothing that will convince you that you need to practice a particular part quicker than hearing the 10 mistakes you forgot about by the time you finished the song, played back in all their un-varnished glory... In the case of vocal styling, it would also let you decide whether you were over the top with the 128 different pitches you sang on that one word, just for "effect"...
If someone in the family has a camcorder you can use, you could accomplish most of the same thing by recording yourself in both video and audio, and using the feedback from that to modify your visual approach as well as other ingredients. Chet Atkins was an amazing guitarist, but he was boring as hell to watch. If Chet was just starting today, he'd probably starve to death or go back to parking cars, or whatever he did before. Even the country music scene has finally realized that TV includes moving pictures...
The bottom line is still: If you love it, do it. Your head is already on so straight I see no point in offering any but technical advice at this point. Seems like your biggest hurdle right now is finding either a higher paying job or a mentor with a lot of idle gear they're not using... Steve