Sorry to have to say that a lot were destroyed in 1922 when they were blown up, it's a nightmare looking for them but the Irish National Archives has started to put what it has on line and the information can be searched at no charge, see: http://www.genealogy.nationalarchives.ie/
If you know what part of Ireland they came from and look at a range of spellings for the name you might find something but don't build up your hopes too high!