Dear Waterlilly
Welcome to Ireland Reaching Out and thanks for your query.
In relation to your search you could consider looking at www.familysearch.org or www.rootsireland.ie (a subscription site) to see if you can find any information about your Kelly ancestors. As I am sure you are aware, the start dates for records in parishes in Ireland vary, depending on the parish, but you may be lucky enough to find some record of the Kelly family, despite the early time frame of your search. Some background information can be found at the link below:
http://www.nationalarchives.ie/genealogy1/genealogy-records/parish-records-marriage-licences/
As an aside, there is a small village called Cloonfad not far from Dunmore. Dunmore is in Co. Galway and Cloonfad is in Co. Roscommon, so this could be the reason why your search is difficult. In fact Cloonfad borders 3 counties; Mayo, Roscommon and Galway. You could try using the above websites to search all three counties. Another suggestion is to search the Griffith?s Valuation records on the link below, as it may provide some information about the Kelly family if they leased land, as they probably did during the 1850s:
http://www.askaboutireland.ie/griffith-valuation/
While the Cloonfad theory is just a suggestion, it may be worth looking into further. The Roman Catholic records for Dunmore begin in 1833 as you can see from the link:
http://www.irishtimes.com/ancestor/fuses/rcparishmaps/index.cfm?fuseact…;
The Roman Catholic records for Kiltullagh (the parish where Cloonfad is located) begin in 1839
http://www.irishtimes.com/ancestor/fuses/rcparishmaps/index.cfm?fuseact…;
Best of luck with your search
Clare Doyle
Genealogy Support