If you get a good scanner and take a high resolution scan you will definitely get a print that looks good at the same size as the original. It is too bad that picture no longer resides in Milwaukee or I would do it for you! It would also be easy to improve the color and contrast on the digital image once you have it, so you could print one as it scans and then print the "improved" version as well.
If you call a few of these places:
https://www.google.com/search?q=onta...E,lf:1,lf_ui:2
I would imagine that they will do all of the above for you for $50-$100.