Swedish song end 60´s early 70´s

I am looking for a swedish song, song by a female swedish singer,
which seems to have been a summerhit in somewhere the end 60´s or
early 70´s. I forgate the name of the singer or the title. I only know
the first lines of the song in phonetic swedish (which must be very
poor!): ,,in oestrai ieven wantrup .....wir habn un osto, ja un
osto...´´.

Who can help me on the full name of the singer and title of this song?

Ruud