You have a large space to fill with sound, 888dewey. Plus, although I am a Pioneer fan, the 519VK is not really a powerhouse. IMO, you need to find a pretty efficient (over 89dB efficiency rating) loudspeaker unless you will limit yourself to background volumes.
If your price range is ~$700/pr., you should consider used speakers. Speakers that use horn-loaded drivers and "wave guides" often offer more effecient operation that will help in your situation. Triangle, Focal, Silverline Audio, DCM and others make pretty effecient monitors. Some Silverline Audio SR-16s are being offered right now on A'gon in your price range.
Are you committed to monitors? For $800/pr you can have DCM TFE100s. I haven't heard the 100s, but the price/performance ratio of the 200s I heard blew me away. Here is a link: http://www.mitekfactoryoutlet.com/products/brand.cfm?brand=6&detail=ok&PN=TFE100&Site=1
I think they come with a 30-day return option. Although they are rated at 88dB efficiency, I heard the 200s in a large convention room powered by a 25 watt tube amp, and they were very impressive - no larger amp was needed.