Hi Noeleen,
Thank you for your message. I hope that someone with information makes a connection with you and helps you to narrow down a parish of origin.
In the meantime have you tried searching on :
www.familysearch.org has a huge database of genealogical records including some church records for Ireland.
www.rootsireland.ie have a large collection of Irish Church records, however you have to pay to use this site.
I did a search for Thomas Cusack in Griffith?s Valuation. This is a property valuation survey carried out in Ireland 1848-64. It doesn't give any genealogical information but can sometimes be used to tie a person to a specific place. There was a Thomas recorded in 9 parishes in Clare in the 1850?s.
http://www.askaboutireland.ie/griffith-valuation/index.xml?action=doNameSearch&Submit.x=47&Submit.y=13&Submit=Submit&familyname=cusack&firstname=Thomas&baronyname=&countyname=CLARE&unionname=&parishname=
Although there is no way to know if any of these are relevant to you they may act as a starting point if you can not find any other leads.
Have you been on the Clare County Library?s Genealogy webpage? They have an excellent collection available so it may be worth your while to have a look at it:
www.clarelibrary.ie/eolas/coclare/genealogy/genealog.htm
Some other websites that you may find useful are:
The National Archives of Ireland http://www.nationalarchives.ie/genealogy1/genealogy-records/introduction/
The National Library of Ireland http://www.nli.ie/en/family-history-introduction.aspx
Genealogy Links: http://www.genealogylinks.net/uk/ireland/clare/index.html
From Ireland: www.from-ireland.net
Irish Genealogy Toolkit: www.igp-web.com/tipperary/index.htm
Kind regards,
Genealogy Support