Karaoke overload - Help

System description.
Receiver:
Yamaha RXV 1000 (purchase date 2000)

SPEAKERS:
front JBL L 300 summit
(purchase date/ DoM 1978 - I inherited the L 300s) Have been serviced OCT 2005 and woofers surround replaced.

Rear JBL L 100 century (purchase date/ DoM 1971)
Center JBL NorthRidge C II (purchase 2004)
Sub woofer Infinity PS12

DVD Changer:
Pioneer Elite DVC-36 (purchase 2000)

Karaoke mixer:
Audio 2000s (purchase 2004)

Video Display:
Hitachi LCD Rear Projection 50V500 (purchase 2004)

Problem:
When I turn up the volume to -32 to -28(fairly loud almost rattling the windows) for Karaoke the receiver trips the internal breaker turning the system off. This is with 6 channel stereo mode selected. However, in two channel mode the same thing happens albeit at a higher volume.

Do I need to upgrade to a more powerful receiver? Or would it be easier to add a second amplifier? I would like to solicit some knowledge advice and feedback. Anyone have recommendations?

When I purchased the RXV 1000 I liked the sound of it better than other brands available at the time (I think it was warmer and I like the DSP programs). I have not kept up with the industry so I am looking for some help. Also the JBL L 300 summit speakers are a recent addition and they replace the L 100s as front channel speakers (I inherited the L 300s from my late father) Every thing works great at reasonable volumes but my Asian family and friends like to crank it up when they are singing Karaoke thus leading to the overload breaker tripping..

I have taken a quick look at the Yamaha line of receivers and the RXV 4600 looks good but has some design issues that may require me to add another amp to power the rear channel. This seems strange to me as the whole point of a receiver to keep the system simple it seems to me that if I need another amp with the 4600 then I should just bi amp my current system. Another option would be to go to the RZ-9 which is much more expensive but also much more sophisticated and powerful.

Or is there a better receiver brand alternative such as B&K, Pioneer Elite, Marantz, Harmon Kardon or ???
Thanks