Looking for Johanna Mansfield of Ireland

I am trying to trace my great grand mothers family background, born 4th May 1818 in Clonmel, Tipperary, Ireland.

Her parents Michael and Bridget Mansfield.

Johanna travelled to Victoria, Australia, marrying William Harwood in 1842 in Melbourne.

They had 7 children, one of which was my grand parent John, born 1843 in Melbourne.

Hope you can give me details of Johanna's family back in Ireland, cheers Rick Silverwood.