$1500 amp budget for Revels HT setup

I have a basement HT with F30s up front (6ohm) & a M20 for the center (also 6ohm). Rest of the speakers are two pairs of Infinity Primus 150s (8ohms).

A Marantz mid-fi AVR is powering them all now...i need a 3 channel or more dedicated amp to get the volume where i need it!

I cannot go above my budget and expecting to go used.