Your shop will be able to advise you on a compatible crankset with the existing bottom bracket.

I don't think you'll get anywhere near $150 for that crank. Look at ebay for comparative values. There is a brand new one on there with a starting bid of $89 with no bids. There is a used one with two bids currently about $27.

A question: why are you already changing the chain? You should be able to get 1,500 to 3,000 miles depending on how you clean/lube the chain and your size.