Kim You will need a name, you need to go back to the person who gave you this information and ask them as I don't think you will find your search easy.
This is the advise I am giving you:
Contact NARA National Personnel Records Center 1 Archives Drive St. Louis, MO 63138 USA
Send a letter to Dr Niels Zussblatt with all the info you have write on the front of the envelope FAO Dr Niels Zussblatt DO NOT OPEN.
You need to write in your letter that you are a child of a naval GI from WW2 and you are requesting all the information that the NPRC possesses concerning your father (grandfather), which is released under the Freedon of Information Act and/or the Court Settlement with War Babes.