On google search "pictures" you have to write in:
adressbuch marienwerder 1926
It will lead you to the cover pape of Marienwerder/Westpreussen inhabitants directory for the year 1926.push on it and you see it online. on page 43 is mentioned a Franz Kowalkowski,butcher, living in Breite Strasse 28. No other Kowalkowskis mentioned. A german city map of this town you will find at the end of the book and than 4 pages back. I could not find information about nowadays polish name for Hindenburgstrasse.