Well, I am going to disagree with Lapierre about the Avalon Eidolon Diamond. (Not that I don't think that they are good speakers - they are magnificient - but, they will not work well with only 18 wpc, IMHO. I believe these speakers really need at least 100 wpc, in order to get decent bass out of them, and 200 wpc to maximize the bass response.)
Personally I think that you'll need to think about going with horns. (I am not a huge fan of the Avantegarde horn speakers, but I do like the Acapella horn speakers. They just seem a bit more refined to my ears.)
Here is a speaker right at your budget limit, that would be perfect. They are 94 db efficient, so the 18 wpc should work pretty well with them.
Acapella Triolons for sale here on Audiogon(Note: I have not heard these, but I did hear their little brothers, the Acapella High Violincellos, and they were great!)
My two cents worth anyway.
Good Luck in your search!