Yes, it IS a small world! Nanaimo is a lovely city. I'm sure your friends who live here love it!
Anyway, I'm sorry but I can't help you with your question. I only serve a small, local area, so I have created a CSV file with only the local postal codes. I can see how if you're going to do it for a whole country the CSV file would be huge and unmanageable.
One thing you might want to check is whether your post office has functionality for looking-up postal codes and calculating shipping costs that could be incorporated into your site? I'm not sure if this is what you're looking for, but perhaps that might save you some time?