Family details prior to emigration to Australia

On 6/7/1865, Margaret Lee was married in Brisbane, Australia, to Andrew Jackson Banning.  From their marriage certificate, we know that Margaret's parents were Patrick Lee and Ellen O'Keefe and that she was born in County Cork, Ireland.  She was born on 26/12/1840 in Mitchelstown, possibly Labbamologga.  Emigration records show that she arrived in Australia on 29/4/1863.

We wish to trace details of Margaret's birth family: her parents and any siblings.