There is a text with tune in Eibhlín Bean Mic Coisdealba (Mrs Costello), Amráin Muige Seóla (Dublin: Talbot Press,1923, 15-18; since reprinted) with the text of a related version. I expect that there are more print sources available, but the Irish Gaelic repertoire isn't my area. Do you possess a recording (sometimes sleeve notes provide useful information) or did you just hear it somewhere?