Searching for Information about my Great Grandfather

John Kelly was my great grandfather. According to my research, he was born in Martin's Town, Athboy, County Meath about 1835 or 1836 andemigrated to Australia (but I am not sure when). He married Mary Meagher in Balranald, NSW on 12 November 1865. While I have been able to find out some infromation on him and his family since then, I am interested to know when and how he got to Australia, and whether there are any of his relations still in Ireland.