Hi There & Welcome
Given the timeline that you are working on it will be tricky to work on your Grandmother.
You can give us HER details if you wish and see can we help.
If your Mum is still alive please don't post any details on her as it goes against the policy of this forum.
Re the County Home
From what I can see online . . .
"Rathdrum was well known in Co. Wicklow as the site of the Workhouse, or as was it known ‘The County Home’. St. Colman’s is still known to the older generation as; The Home’. Today, however, it is the pride of Co. Wicklow, thanks to the work of Sister Philomena and the Sisters of the Poor Servants of the Mother of God, the staff and especially the community. Credit must also go to the Co. Council and Health Board who responded to the work of the volunteers.
"The Nuns first used the name St. Colman’s when they arrived in 1922 but it was not officially accepted until 1949."
You could try and contact the Sister to see if they have any records kept of your Mum.
There is an Irish address here ~
http://www.smgsisters.com/contactus.cfmTara