Home Audio Receiver Deals

I found a great deal on some vintage 2 series Vandersteen's so I bought them, not considering the Yamaha htr 5840 was not up to the task. My question is this: can any Audio Video receiver power these properly? They're ok, if lacking bass, up to moderate volume levels. When I try for loud they clip and the whole system cuts out. I also have a Boston Acoustics cr400 powered sub and BA A-70's for the rear. I use it for movies and music and don't really care how the movies sound. The room (12x15) is just off the kitchen so there are 3 walls and I have to be back against the wall, which does make it hard to hear the surround speakers. I suspect that, on my budget, I should get smaller speakers and an Onkyo or used Denon but I'd appreciate feedback. My budget is $500.