In Newcastle on the 1861 census there is a Catherine married to Thomas Power which according to this census was married before to a Murphy because there is some stepchildren by the name of Murphy living with this family.
Does this sound to be your family ? If so you could contact me on my e-mail genrogu@nb.aibn.com so I could send you the page of the census. If not give me more info and I will try to find something for you on this family.
Rosaline