Hi Carol:
If you have not checked out the Clare Library, it is well worth looking at as it is a great resource for Clare genealogy. I had a quick look for you and I will have a more indepth look again.
The website is here: http://www.clarelibrary.ie/eolas/coclare/genealogy/genealog.htm
I do see a Jeremiah O'Brien family in Killaloe but the dates are in the 1870s and 1880s, and probably too late.
I also see a death for a Jeremiah O'Brien in 1890 aged 74 from Ogonnelloe, but I did not see any births/baptisms with him as a father.
In Ruan/Dysart baptism parish register, I have found a large family with the parents listed as:
John O'Brien and Anne Pyne (Pine).
There is a Martin born to this couple and baptised on 16 November 1862. They are listed as residing in Dysart.
There is also a daughter Bridget born to this couple and baptised on 24 October 1873. The family address is Carhue. This is located in the civil parish of Dysart and is most likely the same family.
You might start there to see if this area is a possibility. If you know the date of birth/baptism for Bridget, that would be a big help. If you also know of any other sibling's names, that would also help.
Please let me know if you need further assistance.
You can email me directly at: jhalloranryan@irelandxo.com.
All the best,
Jane