New bottom bracket/crankset for Trek 1200??
I have a couple of quick questions regarding the bottom bracket and crankset for my old(ish) aluminum Trek 1200. I recently started developing a clank when pedaling. It sounds when I begin to put pressure on the drive side pedal. Upon removing the crank arm, I found that the square hole had become slightly rounded out and had begun to strip the spindle. I have a Shimano 105 crankset on there (FC 1051, 170mm) and I'm not sure what kind of bottom bracket. I assumed I'd have to replace both the bottom bracket and the whole crankset, but the mechanic told me that with replacing the crankset I'd have to replace the whole drive train. I bought the bike used ($200 on craigslist) and have put about 600 miles on it, so I'm a bit hesitant to spend more money fixing the bike than I did to buy it in the first place.
My questions are these:
1. Is there a cheaper alternative? For example, would it be feasible to replace just the crank arms and bottom bracket, but keep the chainrings so that I wouldn't need to futz with the entire drive train? (I don't need anything high end, just something to get me to work without a danger of the crank falling apart.)
2. Is this the sort of thing I should do myself? I don't have the tools, but I do enjoy getting greasy. I'm just not sure that it would be cost effective to buy the tools when I probably won't need them again for a while.
3. Does anyone know where I might found out what type/size bottom bracket would be required for my model bike? Or of any good resources I might use to find said parts and confirm their compatibility?
Thanks very much! And sorry for my longwinded thread!