Newbie wanting advice on HK dpr1001

my system consists of HK DPR1001 receiver. Rotel RB985 amp. klipsch rf82 mains. rc52 center. ss1 surrounds. av123 mfw 15 sub. i love klipsch kill me later. i seem to be missing a lot of mids. i dont seem to be able to drive the rf82 enough or its just me. in your opinion what else would i need to bring my system alive. i am not impressed with my receiver. if i need a new receiver what would you suggest. my budget is $500.00 . i know . times are tough but Audiogon seems to have some used within my budget 75 % HT 25 % music