There are Roman Catholic church records available for Kilgarvan. These date from 1818 for both baptismal and marriage records. You can find these at the National Library of Ireland, Pos. 4290, or the Killarney Genealogical Centre. If you have any difficulty, you could try writing to the parish priest for more assistance.
There are Roman Catholic church records available for the Catholic parish of Glenflesk (where Killaha is). These date from 1821 for baptismal records and 1831 for marriage records. You can find these at the National Library of Ireland, Pos. 4266, or the Church of Latter Day Saints, film 0883747 item 2, 19.
You could try checking the land records called the Tithe Applotment Books (1823-38). Microfilm copies of the books for all of Ireland are available at the National Archives of Ireland (NAI) http://www.nationalarchives.ie/genealogy1/genealogy-records/tithe-applotment-books-and-the-primary-griffith-valuation/ or the Church of Latter Day Saints (LDS). The Tithe Applotment List might be of use to you, or at least interesting for you. These lists constitute the only nationwide survey for the period, and are valuable because the heaviest burden of the tithes to the Established Church, the Church of Ireland, fell on the poorest, for whom few other records survive. The information in the Tithes is quite basic, typically consisting of townland name, landholder's name, area of land and tithes payable. Many Books also record the landlord's name and an assessment of the economic productivity of the land. the tax payable was based on the average price of wheat and oats over the seven years up to 1823, and was levied at a different rate depending on the quality of land. For Parishes where the registers do not begin until after 1850, this information can be useful, as they are often the only surviving early records. They can provide valuable circumstantial evidence, especially where a holding passed from father to son in the period between the Tithe survey and Griffith's Valuation.
You could try researching the two surnames using the Irish Times ancestor website. You can information about the frequency of the name in the mid-19th century and any other variant spellings of the name here: http://www.irishtimes.com/ancestor/surname/ You might then be able to narrow down your search somewhat.
Here are some books you could take a look at:
Barrington, T.J., 'Discovering Kerr', 1976
Denny, H.A., 'A Handbook of Co. Kerry Family History etc', 1923.
Farrell, Noel, 'Killarney family roots book: exploring family origins in Killarney', 2000.
O'Connor, Michael, 'A Guide to Tracing your Kerry Ancestors', 1994.
Don't forget to consider checking estate records:
Landlord: Richard Townsend Herbert: Account book 1709. National Archives of Ireland (NAI), M.1854. Includes Killaha.
Landlord: Herbert: Rent rolls, 1760, 1761. NAI M.1864. Includes Killaha.
Hopefully the names will be recognised by someone living in the local community who can then help you further.
Please make sure you link anyone else in your family who is interested in their Irish heritage to our site - and indeed anyone else you know of Irish heritage.
Genealogist (Ireland XO)