Kilmartin family search

My name is Dennis Kilmartin.  My great grandfather John Kilmartin emigrated to Australia before 1850. His siblngs Mary, Ellen, Johanna & William also emigrated around this time - Mary arriving first.  Their parents are listed n various documents as Willliam Kilmartin & Ellen Rahilly/Sliney/Sheehy (mothers maiden name varies with sources) & bithplace listed as Co. Tipperary. I am currently registering will all Parishes that have a William Kilmartin listed in Griffiths Valuation in the hope that someone will contact me prior to a planned visit to Ireland in August 2013.

Any suggestions or help very much appreciated