Q: Is it possible for the airport express to act as a wi-if range extender while also hooked up to a stereo to allow airplay?

I have a wireless modem from my cable provider that I use for the network in my house. I also have a Cisco range extender that I use to reach the Apple TV I have at the other end of the house. Everything seems to work well. I have tried to add an airport express (2012) so that I can stream music to my stereo. It is too far from the modem to use an Ethernet cable to attach it, so I'm trying to attach it wirelessly to my existing network. The problem is that it often seems to throw the network out of whack. The range extended goes down over time and I have to reboot everything. I think I could solve everything if I could just use the airport express as a range extended and get rid of the other one. But if I do this, can I still use the airport express hooked up to my stereo to stream music via airplay? Thanks.