There are at least seven different locations in the former German Reich with the name "Peterswalde": Part of Koblentz in county of Uecker-Randow in state of Mecklenburg-West Pomerania (Germany). In counties of Braunsberg, Heilsberg, Osterode resp. Schlochau in former province of East Prussia (all three nowadays in Poland). In county of Niederung in former province of East Prussia (nowadays in Russia, Kaliningrad Oblast). In county of Stuhm in former province of West Prussia (nowadays Poland)
Maybe you could give further information about the location to distinguish between those.
If I could be of further assistance please let me know.