here's a possible match for the birth of their daughter Johanna, from the extracted records on familysearch :
Name: Johanna Purcell
Birth date: 04 Aug 1878
Birthplace: St. Mullins, Carlow
Parents : John Purcell & Mary Fleming
Unfortunately there's no reference number in these particular records, and there are two possible matches on the Civil BMD Index :
Name: Johanna Purcell
Registration district: New Ross
Event type: Birth
Quarter and year: Jul-Sep 1878
Volume : 4 / Page : 763
Name: Johanna Purcell
Registration district: New Ross
Event type: Birth
Quarter and year: Jul-Sep 1878
Volume : 4 / Page : 780
On the 1911 census John and Mary indicate they are married 50 about years, so about 1861, so a search of parish records will be required to check for a possible marriage for them.
Shane