Your Pioneer Mixer will connect to that (or other) power amp, and the power amp will power the speakers. The plot thickens further: If you are planning on purchasing a $1000 pair of "classic" speakers, you'd probably be well served to spend say $500+ on a 80-100 watt per channel integrated amp/receiver. The Yamaha RX-797 100WPC receiver leaps to mind, from http://www.crutchfield.com
(it's being replaced by the new "RS" series, which is just a styling exercise). Denon also has several in the same price range, and Harmon-Kardon does too. Any of these receivers have a very good to excellent phono stage built in, and some models will accept either moving magnet [MM] (as your Pioneer does) or low-output moving coil [LOMC or MC] phono cartridges. I think you'll find the sound to be more "musical", but that's always up to you. Don't feel alone. I recently lost my receiver, and am fretting about what to do, how much to spend, and most of the things you are, but on a real "shoestring" budget. When you feel like ripping open your head to let the demons out, you're getting close to a decision!