I also only know some verses in English, but posting them here may help someone else identify Irish-language verses. Is this the same as the song you are requesting?

Oh, William Crotty, didn't I always tell you,
That William(?)Norris would surely sell you,
That he'd come round while you were sleeping -
You left me here alone, och ón, and weeping.

He wet your powder, he stole your arms
And left you helpless to face all alarms.
My bitter curse be on him and his,
That left you to an end like this.

-it may also be worthwhile posting a request at IrTrad-L or Gaeilge-A (both listserv@heanet groups, I access them via www.smo.uhi.ac.uk/liosta)or some of the other Irish language discussion sites on the web (there's quite a few!)