Looking for ideas of where to locate replacement for "vintage" Sugino 170mm crank arm.

I bought my Nishiki Olympic 12 in '83. It is still my main ride. And I ride a lot. I apparently weakened the right crank arm 'round 1984 in a bike-to-bike minor crash, because just 10 days ago the arm broke completely just about an inch below the pedal. Amazingly, the arm did not fail until now.

Soooo, I'd love to replace with original, and saw that I just missed this sale on ebay. Scroll to the bottom to see pic. It is definitely identical to mine, and described in that listing as:

"Nice set of vintage Sugino Tourist forged aluminum cranks branded with Nishiki decals. Nice double crankset for road bikes. Interface is square taper. Crank arms are 170 mm long. Cranks mount tight. Takes standard 9/16 pedals. Threads are in good shape. Finish is clean and shiny. Includes a set of aluminum 52 teeth and 40 teeth chainrings. Big ring also serves as spider for mounting small ring."

Any suggestions or ideas would be appreciated. I've already searched the Vintage subcat Sales, as well as this forum, using search words, Sugino and crank.

Thanks.