Hi Sandy,
the birth records of the Standesamt (civil registry office) Hildesheim for that time are at the Stadtarchiv (city archive) Hildesheim. http://www.hildesheim.de/staticsite/staticsite.php?menuid=404&topmenu=404. I might be able to visit the Stadtarchiv and look it up in the next few weeks. They do take money for that usage of the archive, of course, so we would have to work out a way to deal with that. You can of course write them an E-mail and ask about the information yourself, but I guess that it would be more expensive if one of the employees there looked that up for you.
Kind regards,
Stefan