The above club info is good, you might see if there is any 172s in Abbeyshrule, its right in the middle of the country. Never mind the nay sayers, hotel and food costs have dropped a lot, the club scene is generally very friendly and welcoming to visitors. Outside Dublin the airspace is mainly class G and lightly used. Most of the smaller regional airports such as Waterford and Knock have good facilities at little cost. They do tend to get a bit over protective of their line traffic but once these are not around the airports are pretty much yours. Make sure to fly into the Arann Islands when you get here, best use of a light aircraft. ALWAYS check ahead to see if avgas is in stock (even at big airports) but usually no problem. Most grass fields are quite short even for a 172 so check carefully. Enjoy!
ps, it hasn't been called 'Southern Ireland' since 1922, Ireland is the correct name or 'The Republic of Ireland'.