To be fair that amp would be able to run that set up.. You would need to go into the speaker unit itself and parallel something to make it 4Ohm (I'd have to open it up and see the wiring which is why I said something) {which I have done for my friends set up} then parallel both of those down to 2 Ohm load which it would pump out 850 total divided by 2 so it would be 425watts per side. The PEAK for those units was 700 which leads me to believe the RMS is right around 500 (on a good side if its 500) on a low side of 300. If its on the low side of 300 you can do a coil power loss for RMS. Doing this on my friends Yamaha speakers I wound up 200ft of wire and dropped it so it was at the right wattage when it got to the speakers. (very unorthodox but it works) The speakers themselves yes were built to be loud but they don't actually do a bad job for his theater that he uses for his PS4 (which I at least put an ssd in for him) and its really not bad. Its way better than most stock car stereo systems and the walmart brands out there.
Ok, PA speakers are really not necessary. You should look into Polk Audio (something like the Monitor 60's, while they have been discontinued, you can find them on the cheap if you look hard enough) I have a pair, and they pump out some serious, quality sound for the price.