Hi Evaann
Welcome to Rootschat! I know what you mean about Armagh Ancestry - I too have spent a small fortune on trying to find my Hughes in Armagh. I have a Sarah Hughes - (born c. 1860) she was my Great Grandmother, also from Armagh - not sure what parish but possibly Markethill or Richill. Hughes is such a common name in this county, but you have a head start knowing the names of all those siblings. If she was born in c. 1896 you should be able to get the civil registration from the GRO - they will do a search for you (within five years I think) if you can't get to them in Dublin.
Also, if you can wait a little while, the 1911 census for Armagh will be online (sometime this year) and will be fully searchable and free.
Good luck
Jaylay