Welcome, I'm sorry I can't be of help. I gotta say, I havn't seen too many posts about Ireland in here. If you have any good stories, I would love to read them, and Im sure others here would too.
Welcome to StP ... can't help you personally ... stayed in a lot of squats in England, but did not squat in Ireland. Have been to Galway though in 2014, stayed in a hostel there. Nice town.
Anyway, I found this site, perhaps people there can help you with contacts:
I was in Galway this last summer. Didn't see any squats, though did squat the forests by Merlin's Castle. I squatted in Letterkenny. I am outside of Dublin now, housed, but looking for squats for when I have to evade immigration again. I'm a yankee in Ireland.