Advice for buying a new crankset for my bike
You're doing the right things. Since that crank was made, Shimano basically has completely dropped 30/42/52 all across the board in favor of the more practical 30/39/50, which is good in many ways (most people using a triple have no need for the 52). The A073 will work but the gearing will be different. It's also a non-replaceable chainring crank, and personally I think it's always a little sad to put such cranks on bikes that actually get ridden, although it's not a huge deal because the steel rings will last a long time.

If you wanted a crank that was a) Shimano, b) a 100% drop-in replacement including ring size, c) has replaceable rings and d) still real cheap, that would be FC-2303, still available on ebay. (Also this isn't a likely-to-become-outdated recommendation, because that model will probably remain the last one Shimano ever made that fits all those criteria).