Looking for details about my grandmothers family

[Katjuscha]

Hello to all of you!!
I am Katharina and I live in Vienna - Austria.
I try to find out more about my grandmothers family (names, dates and places of birth). She was born in May 1900 in
Cernowicz. Her familyname was BERNEC.
Is there anybody who can tell me, where or how I can get
any information about this city or the registration office.
I would be very glad to get an information.
Greetings from a sunshiny day in Vienna.
Katjuscha