There is information on different courses in Ireland here.
Don’t think that a traditional arts course is off-limits to you. Teachers are there to teach. With determination they’ll help you to improve your skills. It’ll really benefit you when you go onto digital art. Employers like to see it on a CV as well.
More degree courses are popping up here, but they’re more focused on game programming and development as a whole. It’s best to go to Scotland or England for a good digital art degree – eg. Abertay, Teesside. Maybe you’d be better off doing a one year course to make sure it’s what you want to spend the rest of your life doing. There are a few colleges in Ireland that accommodate for that, such as Ballyfermot in Dublin.
Will 3D modelling stand on its own? Not really. Some studios will hire a 3D modeller, but that’s generally only with large teams – eg. EA. Even then you’d be expected to be able to understand how other programs work. More likely is you’ll need to learn 2D art and animation.
There are a few job opportunities in Ireland, but there’s not many. You’ll probably have to cut your teeth in Britain for a few years at least. That’s where a lot of people on this forum are working.