Polish romantic music?
Lady Punk, Varius Manx, Perfect, De Mono....google it...
Opera or Musical?
yawn.... zzzzzz........ ;)
my ideas....go for a walk...picnic in a park with some Polish goodies... coffee/drink in a place where is live music and you can sit outside (what's the weather there?) .... maybe movie at home after dinner he makes for her.... flowers is a must, roses are over rated, go with some other flowers... candles...and yes, a few Polish words would be impressive...