Need help searching

I am trying to find my GGrandmother Mary Donellan who I believe was born to Michael Donellan and Mary Kelly. I have them being married in DonaghPatrick June 7, 1845 and would like to find out if they had any children while in this Parish. Michael was born (I think in Loughrea parish in Oct 1820. I dont even know where to begin to search for Mary since most of her records have her parents being Michael and Mary and one record has them as Patrick and Mary Murray.

Any help or guidance would be appreciated

Pam