Reilly Costello Dublin

Hi. Please may I ask if anyone can help me with a query about Roman Catholic Churches in North Dublin and also if anyone knows how I can find the following out:

Baptism and Birth of Elizabeth Reilly born 5 March 1875 in Dublin.Parents were Patrick and Mary Costello Reilly {could also be spelt Riley}

Margaret Mary Reilly born 9th June 1879 Dublin.Parents were Patrick and Mary Costello Reilly.

John Christopher Reilly born 21 st December 1876 Parets were Patrick and Mary Costello Reilly.

As far I am let to beleive, they were all baptized at No.2 North City, The City of Dublin, Ireland.

Please does anyone know where the Roman Catholic Church is in No.3 North City ?

Or how I can any information on this family or how I can locate a Marriage for Patrick and Mary?

I beleive its the second marriage of my Great x2 Grandma Mary Costello whos first husband was Edward Costello who was listed as both a Joiner and an RIC policeman.

I would be most gratful for any help or advice, I have spent more than 3 years looking for this side of my family.

Thanks a million

Annette x