Marantz 5400, Elite vsx52,H/K 330 would all be good match's with your Polk's as would any other model in those lines you can afford. What Polk models do you have ?
The HK AVR430/435 or AVR630/635 would be better than the AVR330. Marantz Sr5400/SR6400 or NAD T753 I if your willing to search around I think all can be purchased for under $800.