There was a BIT of history as you say on the church website. You could try Four Courts Press to see if there is anything there or Eneclann (Trinity College). Did you try for the local library as you would think they would have a copy of any books about it!
There is a CD in the Eneclann shop about the Diocese of Elphin and north Roscommon?
I don't think there is anything more I can offer. Annette