Power Amp for Roksan Caspian system

I may be caught up in an add-on fever, at the moment, but I am looking at adding a power amp to my in-transiton system. So far, it consists of a Roksan Caspian 70-watt Integrated Amp and the solid Roksan Caspian CDP. I am thinking of an amp with some muscle, 125, 150, 200 watts - something which will team well with the Roksan integrated as a pre-amp or will match up to bi-amp (is this a good idea or even possible to bi-amp with different make amps?).. I have detoured onto this path during my search for speakers(!) I am looking to strongly power the speakers-to-be-named-later, most likely stand-mount monitors. $500/$600 or under for a used amp. Any thoughts? If you have any speaker ideas, $1500 or less, please feel free. I love listening to music as I roam the house, feel it more than study it. Thanks for any and all considerations.
Just in case you weren't aware, Roksan makes a power amp in the Caspian line which is perfect for bi-amping. Good luck.
I second the recommendation of biamping your integrated with the Caspian power amplifier.Adding the Caspian Power amp is a pretty significant upgrade.
Use the Caspian Integrated to run the tweeters and the Power amp for the mid/bass drivers of your loudspeakers. This frees up a considerable amount of power to the preamp section and will give the presentation more authority, body,clarity, dynamics, transparency and increases resolution, air, and soundstaging in all dimensions.
Bass becomes punchier, tauter and more tuneful.Boogey factor is way elevated.Music becomes less strained, more open and expressive.
IMO,it's the best performance to value upgrade for the Roksan Caspian system.
Grazie, Timrhu & Caterham...I neglected to mention I had been looking for a Caspian power amp for about a couple of months now, with absolutely no luck. This lack o' luck led me to think about different amps and the possibilities. I think you are both right, though, I should keep lookin' for the Caspian. Grazie, again ya'll! Jerry