You need to indicate what sort of climbing you're seeking. Sport? Multipitch trad? Hard/easy?
If I were doing what you're doing I'd schedule a few days at Paklenica in Croatia. I haven't climbed there specifically (have climbed elsewhere in Croatia) but it's on my list.
If you wanted to go further up into Austria I can make some recommendations. The closest I've climbed to where you'll be is eastern Austria, long multipitch or short sport. I've climbed at The Rote Wand which was good: http://www.bergfex.at/sommer/steiermark/touren/wanderung/3463,rote-wand-steinbockparadies/
(note there are at least two Rote Wand's in Austria, and the other one is better known).
Only a short drive up from the Slovenian border.