Add an amp to my receiver ??

Yes, you are correct.

I added an Anthem MCA-20 225Wpc stereo amp to my Onkyo 747 A/V receiver and am very happy with the results. Going from a claimed 80Wpc on the Onkyo to the 225 on the Anthem didn't gain me much in the way of absolute volume but what I did get was much better bass response and imaging in stereo. The extra power on the L-R doesn't overpower the center channel too much when watching movies. I'll eventually add a better power amp for my surround channels but surround isn't my main concern for purest fidelity when watching movies. When listening to CD's my measuring criteria change significantly. While I am willing to put up with adequate sound on movies I will not accept anything less than excellent on stereo sound. I intend yet to add a two channel preamp and pass the SSP through the preamp. This will save the cost of a second set of speakers, amp, and the required cables. It's having your cake and eating it too so to speak although many purists might disagree. Consider an amp to improve the quality of the sound over the A/V receiver not just as a way to get more dB's out of it. If louder volume is you chief concern then I would recommend a more efficient set of loudspeakers.