According to my research there are four branches of Agars in County Carlow. Suggest that you might try to get a contact in each branch. Some names are listed in the "World Book of the Agars", but I could not establish a continuing correspondence link.
Every time I do any research on family name I keep coming up with the names of Agar-Robartes, Charles Agar-Archbishop of Dublin, Earls of Normanton, and Lords Callan and Clifden. I often wonder if one can honestly claim any association with these nobles and their coats of arms. Try ttp://www.stirnet.com/html/genie/british/aa/azmisc02.htm.