It would be very helpful if you knew where in Greece your father's family was from and when they emigrated. If they came to New York in the early part of the 1900s you may find some relatives at www.ellisislandrecords.org by searching for Coulouris or Koulouris. Also check out Social Security Death Index: http://ssdi.genealogy.rootsweb.com/cgi-bin/ssdi.cgi/
and troll the intrane. Good luck