Daniel Leary/O'Leary in Tankardstown

In the 1830s there were two churches (or chapels as they were referred to at the time) for Killmallock Catholic parish - one in the town of Kilmallock which was likely the parish church, and a second to the south east at Ballingaddy North townland - see the attached Google map.

The old church in Killmallock seems to be gone, it was located to the north of Sarsfield street between the street and the ruins of the old Abbey, close the the Church of Ireland church ath that time - based on aerial photos it was probably where a small car park is now located, opposite the old tower. The current Catholic Church, St. Peter & Pauls, is on the other side of the main street and to the north west.  I've attached an extract from an aerial map from Google showing the area - with the main street, the old abbey, the tower and the site of old Catholic Church all marked

There's still a church at the same location in Ballingaddy, possibly slightly upgraded since the 1830s - see attached photo from Google Street View.

Tankardstown townland is to the north west of the town of Kilmallock, so the church in Kilmallock would have bee the closest to your Leary family's house.