Tracing family history that far back can be tricky!
Before 1864 records were kept in the form of church and parish records; while some of these have regrettably been lost over the years, all the surviving records have been sorted into county-based genealogical centres. The centre for County Limerick
would be a good place to start.
We also have some community forum posts already that have Helpful Tips
and a Three Step Guide
which you may wish to take a look at too.
I'm sure our fellow members will have some ideas for you as you try to piece the information together.
Have you ever been over to County Limerick before?