Ancestry has the records of two sibling to Christopher.
Sarah baptised 24 Mar 1844
Mary baptised 31 May 1846
You can view the original records in the parish registers for Glendalough here.
I did not find any marriages recorded that seem to fit these girls.
I searched for a marriage record for Patrick and Elizabeth but no luck. Perhaps a trawl through the parish registers may provide you with some more information.