orphanages in Poland
The closest to the Czarny Dunajec seems to be this one in Zakopane: domydziecka.org/placowka,207.html
Looks like a Polish name: Kasia - diminutive from Katarzyna in Poland, and Leja - a surname (and very popular in the Czarny Dunajec/Nowy Targ area): moikrewni.pl/mapa/kompletny/leja.html
Bożena - Polish first name.
Katarzyna Leja could be your mother's name - but this is just a guess-work.