Hi There and Welcome WeriBeau
I'm a McDonnell, a Dublin one though and it has been the hardest surname to research.
Frustrating to say the least when it's my own name.
My own bloodline flip flopped through numerous variations in spelling.
Anyway, just to let you know that Catholic registers can be viewed for free at nli.ie
I will say though that I'm afraid that you simply don't have enough info yet.
You need Mum's name PLUS her maiden name.
Then you need an exact townland for the family to see if records exist for that parish and timeline.
Tara