We live in the North of Ireland but I worked in Dublin full time for three years (until about a year ago). I was staying down during the week and coming home to the countryside at weekends. At first when I moved in 2008 I was horrified by how expensive everything was, but by the time I finished prices had come down a lot. I wasn’t running a car so I have no idea what costs would be like. If you have children then you may be surprised that you will have to buy all their school books – but many schools run swop schemes.
As far as I know there is a good small holders network and slow food movement which you should be able to make contacts with. If you are eligible for any types of social security the rates payable are much higher than the UK. Rural areas and small country towns are far more diverse that they used to be and local populations have welcomed the “new” Irish families.
For more information on things like social welfare, opening bank accounts I suggest you look at
http://www.borderpeople.info/index.htm This website is aimed at people living on one side of the border but working on the other, but much of the info may be relevant.
Good luck with the move!!