Bicycle Tutor

Hi - please forgive my newbie questions:
I have a thrift store bike that I'd like to use for short easy street rides. The bike is a Bridgestone Kabuki Skyway. I've done some research and know that it's an old bike probably from the late 70s early 80s and that it is Japanese.
Here's the problem - one of the chainrings is bent (not just a tooth but the whole ring). This causes the chain to come off - I know that my bike shop could try to bend it back but that doing so may not work/fix the problem. The chainrings are weird - only three bolts with a measurement between two adjacent bolts of 90mm (approx). My online perusing tells me that I probably can't find a replacement chainring.
So - can I just replace the whole crankset? How do I know what will fit? Will any 3 chainring crankset work? Thanks for your help (and patience!)

I don't know much about what came on this bike, but from the few online photos I see, it looks like a fairly standard two chainring crankset. Your's has a triple?
I would think any normal road crankset should work. I'd stay away from the more high end current cranks that are made for 9/10 speed drive trains.
Here's a decent very low cost road triple:
http://www.cambriabike.com/shopexd.asp?id=45378&page=SHIMANO+FC-2203+TRIPLE+ROAD+BIKE+CRANKSET
If you do have a triple, note that mtn bike cranks will have lower gearing than on a standard road crank.
Do you have the disk brakes? I had no idea they were around that far back.

I forget to mention - try straightening the chainrings first. I've actually had pretty good luck doing this. Although once they've bent once, they are a bit more likely to bend again.
Take the chain off the chainrings so it can spin freely and then just carefully bend the rings back to a straight line. Keep spinning the cranks so you can see where to adjust. Best to use smooth jawed pliers or an adjustable wrench if it will fit in there.

Thanks DaveM - I'll try to bend the chainring back but wanted to have a backup plan. I appreciate your help!

I also double checked the crankset and it definitely is only a double - don't know why I said it has three...either I can't count or I just mistyped. Good catch!