I checked www.rootsireland.ie/ but the earliest Clonguish C of I baptisms are 1820 so no Ellen I'm afraid.
I double checked the RCBL website and their Clongish records only start in 1820 also.
The marriage record is on rootsireland but doesn't have her parents' names!
Date of Marriage:21-Jun-1821
Parish / District:CLONGUISH
ClongishDenomination:Church Of Ireland
Church Of Ireland
I wonder if she was named after this Eleanor:
Name:EleanorRossDate of Death:11-Aug-1820
Age:67Parish / District:CLONGUISHAddress:LisnaboeCounty:Co. LongfordStatus:Not RecordedDenomination:Church Of IrelandOccupation:Not RecordedSex:Female