I can recommend this place:
http://www.delphimountainresort.com/
No affiliation, just a satisfied customer.
We stayed there last year with another couple and we had a fabulous
weekend. We stayed in one of the 2 bedroom apartments and it was
really nice and relaxing. Good spa facilities and loads of activities should
you be inclined to partake.
It's a lovely part of the country for spinning around aswell if you want to
take a drive. It has a nice restaurant and bar and gorgeous mountain views.
The only downside, is that it's a long spin from Cork, but if it's a long
weekend it might be worth it.
If you want to go closer to home, Parknasilla near Kenmare is supposed
to be nice aswell, but I've only heard this from friends, haven't been there.