The Irish tax system regarding rent from property obtained in other countries is complex. You should only be paying tax on the income minus expenses (i.e. actual profit). However, our Revenue Commissioners don't see it this way. Get advice from a sound accountant and have him/her return your total income. It will cost you a few bob, but will save you lots on worries.
If you wish to go it alone, then consult the Revenue website and best of luck.
(Thinking out loud - Get a Tax Accountant on board and fast).