What is most likely to come up?
my teacher told me that its unlikely for bronze age to come up but that Irish metal work is likely. Im not too sure tho I dont know what to study myself
As long as you know your Stone Age, Bronze Age and Iron Age you should be okay. It's important to know all three!!! Some people will leave one out because it came the year before but you are better off knowing all three to be on the safe side. As well as that you can study the Early Christian period as well. You can get quite good notes on your Irish section online.
http://www.studynotes.ie/leaving-cert/art-lc/hugh-lane-essay-plan-gallery-question/ (gallery,link for Van Gogh + Degas on page)
http://arthistoryleavingcert.com (some good notes here but a bit limited)
http://resources.teachnet.ie/jshortt/files/high_crosses_essay_1.pdf (sample essay about high crosses)
http://magheneart.blogspot.ie/p/art-history-notes.html (most of the Irish section)
http://www.boards.ie/vbulletin/showthread.php?t=2055534840 (Bronze Age,La Tene,Monet,Renoir,Gothic,Gallery)
Good Luck! :)