Center Channel on an Integrated Stereo Amplifier


Background: I have an integrated 2 channel amp for stereo listening. I added a sub to it with a direct connection to the terminals on the back of the amp (2.1 setup right now). 
I also want to have a Center Channel that I can connect and disconnect when I want (so I can listen to the 2 channel for music and have the center channel connected for movies). I have a really good amp, so I would love to be able to use that amp to power the speakers when watching movies (and power the center channel too if possible!). 

Question: What is the best way for me to get this done? 
For me to have a 3.1 setup - a 2 channel integrated amp with 2 speakers, a sub, and a center channel WITH connectivity options so I can disconnect the center channel whenever I want. 


Thank you all for your help,
Shawn 
shawnpmathew
A 3.1 or 3.2 setup can work really well.

But I'm not clear on how you are processing/sending a true center channel signal and which amp (or amps) you are using? Can you elaborate?
@jl35 - I do sit between the main speakers. They are set up now pointed in toward a sweet spot. 
Thanks for the advice
@david_ten - I do not have a processor to send a true center channel signal to the center channel. That's why I am asking the question, so someone can guide me on which processor can do what I am looking to do. 
I have a pair of ML speakers driven by a PrimaLuna DiaLogue Premium Integrated amp, and I also have a REL R-505. That is my 2.1 setup. 

I want a  way to add another channel (a center channel) to this setup. 
Post removed 
the other issue is matching the center to the mains...I'm actually in the process of turning my 5.1 into a 2.1