Bill,
You might also check with the Allen County Public Library in Fort Wayne. I know that they have the NARA Compiled Service Records they may have the film that John is speaking of as well and since Fort Wayne is an easy drive from us it has the advantage of same day service!
As far as your efforts to place a new tombstone on your ancestor's grave I believe that we may be able to supply an SCV honor guard and several UDC ladies to conduct a dedication for the tombstone and an Iron Cross if you wish.
Contact me!
Steve Ritchie
Muncie, Indiana