If you're extra-especially nice to me I might just take a wander over there on Thursday and see if it's where I think it is.
Otherwise I remember seeing the picture of the general area from 1847 I have (allbeit somewhat before your Mum's time) in Pat Liddys 'Dublin' book in Easons or some other bookshop, it's on sale all over the place.
Just look at any modern map of Dublin, or rather the street index and you'll find if it's still there now.
The Dublin Directory from 1850 which is always handy turns up results on-line - a painter, musician, a person who's occupation isn't listd and appropriately for here - an architect, were just some of the residents in 1850.
The Ntl Archives on Bishop St will give you census records for when your Mum lived there if you want to bring back memories of the neighbours