The problem is YPN itself. Look at your CTR: That means two things Your ad placement is very wrong ( but I suppose you have been playing with it). The ads are not attractive for the users (reason I dropped YPN some time ago). Beside using targeting (if it's still possible) there is not much you can do.
Thanks guidyy, I couldn't find a better replacement. I used to use Bidvertiser, but their ads are totally unrelated, and i get no hits. I would've use adsense, but i was banned.