Best answer by melvimbe
Second, Sonos really can't utilize your existing speaker setup. Don't know if you plan on getting rid of those as well.
Third, if you're willing to keep your receiver, you can bring that entire setup into a Sonos system using the Sonos Connect, it can pass input to your receiver and, depending on your receiver, take output and pass it on to other Sonos speakers in your speakers.
I'd recommend the 3rd, but not really sure what your ultimate goal is.