I believe it is somewhere around 25,000 euros (US$40,000!!!) and you would get your type rating after you are hired from the company that they use. You probably already know this but you need JAA license and if you don't have time on aircraft over 12,500 you will need to complete MCC course which also costs a few thousand. You obviously also have to have an EU passport. Ireland is also getting ready to experience it's first recession since 1982 so keep that in mind before you invest alot of money. It also costs a lot to live in Ireland. There is a high cost of living over there, housing, food, cars, gas, auto insurance (especially if you are under 25 and male) is also extremely expensive.

My cousins friend just paid 29,000 Euros for the type rating so he could work for Ryanair. I don't know that is a lot of money and especially if you are an American with the exchange rate of the dollar now. Are you sure that Aer Arann is hurting for first officers? I know they are always looking for direct entry captains but there is lots of low timers in EU that are looking for any job they can get normally. Also Aer Arann will only help you with the conversion of FAA - JAA if you have lots of PIC time in the ATR (you probably know already)

My info is all second hand so take it for what its worth