any ideas on where to get this nervar crank ?

Hi everyone,

Allow me to begin with saying that im a newbie in the bicycle world. I've bought this mid 80's/90s (IDK, but it's on reynolds 501) Peugeot on the internet a couple months ago and have been riding it daily until a minor accident happened, after which the left crank bent… the pics don't show it, but it turns poorly, stops at the bike frame and I can't push it any further.

I took it to a local bike shop and they told me that I should get a new crank and replace it myself. It's a Nervar, and the screw is marked "8-8-14", although I've no clue what that means, and I couldn't find much on the internet. Im not quite sure what should I get, that's why I wanted to ask you for help:

1. How can I be sure im getting the right thing? Say, here's an e-bay auction, and this part looks very similar to what I have. What should I measure to be sure I know what im looking for? The screw's head is about 1.5cm and the crank's length is 9cm.
2. Should I look for the exact same part, or are there any alternatives? I'd have to get a Nervar from abroad, so I wouldn't mind a cheaper solution if available.

Thanks!