You do not give any dates or parent's names for John or Sarah. Have you tried looking at the LDS on-line IGI records yet? Try the website http://familysearch.org/
There are IGI christening records on-line for a "Joannes"(John)QUINN, dated 28 Oct 1845, and one for a "Sara" QUINN, dated 30 Jan 1859. In both cases the parents are: Georguis QUINN and Margarita CONWAY. The records are from the Roman Catholic, Drumcliff & Magherow, County Sligo. (I don't know if these might be yours, but thought it might help.) Good luck.