Filling for pillows, and possibly a bean bag sofa...

Look up upholstery firms in the golden pages (i dont have the dublin one). You will need best grade (firmest) foam, minimum 4 ins thick, 6 would be better. It is very expensive, get it cut exactly to size (bearing in mind that if you cover cushions you need the foam to be marginally bigger than the cover to get a snug fit.

You could use a softer quality foam for the back cushions which would be a bit cheaper. You can buy upholstery fabric in shops that sell curtain fabrics, but if you look around you might find somewhere that does specials - Fabric World in Kilkenny might have another branch in Dublin, or Murphy Sheehy is a treasure trove of fabric (assuming they are still there, its years since i was in there). Do buy furnishing fabric rather than curtain fabric though. You need polystyrene beads for the bean bag, cheaper in a builders supplies shop than a curtain shop, keep any left over beads as they tend to squash after a while and need to be topped up.