A very good desk..
Put you'll need a poweramp to push the speakers mate.
Why not downgrade the mixer you are using.
And invest a few dollars in a good poweramp.
Depending on the wattage handeling of the speakers get yourself a stereo poweramp to suit. Say if the speakers are 300 watts each.. get a 2x300 watt poweramp.
Look on Ebay for some decently priced poweramps.
Run it off a mixer like this one:
http://www.behringer.com/UB1222FX-PRO/index.cfm?lang=ENG