Hello Mary,
My grandmother was Alice Marie Gruber. Her mother was Mary Katherine Gangl who came from Illmitz. My grandmother was born on January 18th, 1897 in St. Paul Minnesota so it's possible that we are related. Mary Katherine's husband was Frank Gruber, also from Illmitz. I don't have any other information than that. I don't know when MK and Frank immigrated to the St. Paul area but it may be possible that your grandmother Barbara is related to my great-grandmother Mary Katherine.
How was your trip to Illmitz? Did you find any living relatives? I would be interested in any genealogy information you might have on the Gangl family in St. Paul and Illmitz. Warm regards, Leandra Little, Weehawken, NJ