You have there approx. $20 thousand (when new) system.
Setup is not easy - until you know what you are doing that is, it takes a while, RTFM many times. But it does sound great when correctly setup.
It is all digital so you won't need that amp you were looking at smile unless you want to go analog frown
At a later date I would keep you eyes out for DSP5000, 5200 or even 5500 to replace the front L&R and use the 33 as rears.

561, HD621, DSP5000s(24/96), DSP33C, DSP33 surrounds, Pioneer DV575A CD/SACD/DVD-A, Panasonic DB170
(561 to be replaced with G68 shortly.)