Hello Karen,
It's so lovely to hear you'll be visiting Dublin soon! 
Regarding a recommendation for a breakfast place, I'd def suggest for you to check out the 
Natural Bakery. A wee place that makes great breads and pastries daily, from scratch and with top quality ingredients. Best part is that, it's about a 6 minute walk from the Convention Centre. A wonderful choice located right on North Dock!
Be sure to check 
this link for more coffee, delicatessen and bakery options in 
Dublin! 
Have a lovely day and enjoy your visit! 
:)Romina