First, find a modern HDMI equipped receiver (AVR) that will adequately power your B&W's. Modern receivers are like Swiss Army knives and try to be all things to all people and as a result, there are trade offs - especially in the amp sections and power suppples.
You have a nice pair of speakers. I also assume your old receiver is a 2 channel stereo model. So what was the power output of that receiver and were you satisfied by its ability to drive your 602's? Then find an AVR that will spec out the same with 2 CHANNELS DRIVEN ACROSS THE ENTIRE FREQUENCY RANGE, 20 Hz -20 Khz. Your old receiver was probably rated this way but specs on new AVR's can be misleading.
Finally, while B&W's are nominal 8 Ohms, they do have impendence swings below 4 Ohm which is why B&W's often sound better using higher powered amplification. I would look at AVR's rated into 4 Ohms. The new Pioneer SC models are and their new Class D3 amps have been critically reviewed and well received. The Pioneer SC1222 & SC1522 can be purchased at your budget with some smart shopping. Google these models to learn more.
Finally whatever AVR you buy, make sure it has a full set of PRE-OUTS. Many don't. This will allow you to add external power amps down the road if you ever feel the internal ones on the AVR are no longer cutting it. Hope this helps.