Any particular features you need on the 3312?
Otherwise, you can get the Denon 990 (clone of Denon 3310/3311/3312) for $638:
Amazon.com: Denon AVR990 7.1-Channel Multi-Zone Home Theater Receiver with Networking Capability and 1080p HDMI Connectivity: Electronics
For external amps, there are several routes.
1) "pro" amps like QSC, Crown, Yamaha, Behringer - but they do have internal fans -- so slight noise
2 "budget" amps like OSD AMP300 for $346:
Amazon.com: OSD Audio AMP300 2-Channel Dual-Source 300-Watt High Definition Power Amplifier (Black): Electronics
It is 150wpc x 2ch 8ohm, 250wpc x 2ch 4ohm, stable to 2ohm. Even has the blue UV power meter like McIntosh so you can monitor how many Watts you are actually using.
It has variable gain control like the pro-style amps. The AMP300 is a solid state amp, and no fans, so quieter than pro amps.
3) "mid-budget" amps like Emotiva. Very popular.
Could also get the 200watts monoblock amps for $350 each from Emotiva or Outlaw Audio, so 2 monoblocks = $674:
https://www.outlawaudio.com/mofcart/combos.html
4) "mid-high-end" amps like ATI amps.
Amplifiers