I research the Irish Family History Foundation's database. It contains 12,800,000 surviving rcds for abt 70% of Irish counties. Rcds are increasingly sparse B4 1840, rare B4 1800. Cos. Donegal and Derry were recently added to the database.
Note 1 - Without a KNOWN county, the chance of an ancestor's rcds NOT being in this database is AT LEAST 30%.
Note 2 - Only 1/2 of Co. Cork's rcds are in this database.
Note 3 - The RC church kept control over most parish rcds from Tipperary (north). These are ONLY available thru the Tipperary Family History Research center at a substantial fee (regardless of outcome).
For Ann McNamee B ????, Co. Longford, the earliest rcd is in 1836. This doesn't fit your timeline.
For Ann McNamee M 1845 +/- 4 yrs, I found 0 rcds. The closest are in the 1860s.
For John Kiernan B 1846 +/- 1 yr, Co. Longford, with a father forenamed John, I found 1 1847 rcd, Mullinalaghta RC parish.
For Mary Kiernan B ???? ditto, Mullinalaghta RC parish, I found 2 possible rcds: 1854 and 1856.
Google the Foundation's name to lead you to this database. Register, opt to be notified as rcds are added and browse. Pls post your search results to my genforum msg.