Just wanted to mention that if you figure out a parish, you can register with the Gathering (the big hoopla Ireland has going on in 2013, welcoming all the diaspora home) and there appears to be some genealogy research help being offered. So this might help you out when you are onsite. The website says to register the sooner the better.
General link: http://www.irelandxo.com
Registration link: http://www.irelandxo.com/visiting-ireland-2013
Best of luck!