If you are going to be at the airport for 4 hours, buy a newspaper. You will NOT get a good fried breakfast at the airport. In fact you would be hard pushed to get anything worth getting excited about.
Dublin airport has one terminal at the moment, and the food leaves a lot to be desired. Don't expect much.
Hope you find a way to pass the time.
we were just through there last week and had no luck whatsoever, but perhaps it had to do with which terminal we were in. we were fying ryanair to leeds and there was no much of anything in the terminal other than a coffee shop.
good luck, maybe if you are in another terminal, there will be more options.