In looking for info on my great-great grandmother Catherine Shea (alas, not the same as yours), I did discover a record of one Catherine Shea born in Newtowncashel, Co. Longford, Ire., in 1833. I also came across an Elizabeth Lawler, whose father was Michael Lawler; the record indicates that she was baptized in Co. Kildare in 1870. The source for these record is: http://http://ifhf.rootsireland.ie
It's a site that sells these records for 5 Euro (roughly $7) each. You can search the site for free and find basic info about people, but to get the details (e.g. baptismal records that list parents' names, etc.) you need to pay.
I hope this info helps. Good hunting . . .