so how basic?!
If you're in Ireland you could try going in to a bookshop that the kids get their schoolbooks from. Don't know if they'd stock any off season but might have at least some names of books that they use as irish readers, although saying that, I don't remember having Irish readers past about 2nd class. that might have changed though since then.
what i've done is read books in irish that are geared towards young teenagers (or younger), like age 10-12(ish), cuz the stories aren't REALLY childish but the vocabulary they use is such that I can actually understand it. And if there's some words I don't understand there's not that many that I give up altogether and I can actually learn them because the same ones will more than likely crop up again throughout tyeh book.
i've just picked up these as i find them, but try any bookshop (doesn't even need to be that big) and they'll have some books in irish for children. i always try reding the back cover/first page and if see how much of it I understand.
I like the story "An Gruagach" by...hmmm...don't know who it's by, i'll look for you and post asap
So if you're not in Ireland, try the internet and buy the books from online,try http://www.litriocht.com/shop/
Most of the books have a review. I always think Amach by
Alan Titley looks good but haven't been near a shop to get it yet, but that sort of thing anyway. just make sure the book isn't too long. any that i've bought haven't been more than 100 pages probably. It'll take you a while to get through them the first time you read them so any longer and you'll forget what happened on the first page by the time you get to the end!
anyway good luck with your searchings!