For further info about the history of Carrigaholt castle (and West Clare) I would recommend Paul Murphy’s book ‘Cuchulain’s Leap’, ISBN 0 9518849 0 5
Clare Library also provide history and historical images on their site, here are some direct links referring to the castle. There are many more articles on their site but these should provide a good start:
Carrigaholt castle:
Carrigaholt, Loophead (1891)
Others:
Death of Teige Caech, and extinction of the line of the chiefs of West Corcabaskin