Yes, if you are prepared to not connect to the internet whilst connected to the TC.
Wireless card in the laptop can only connect to one WAP at a time. It can therefore not connect to the TC and the Internet modem router.. nor can the TC cannot to a non-apple router by wireless and offer a separate wireless AP.
So the correct way to do this is to bridge the TC.
Then plug it into the main router by ethernet.
Then you can setup wireless any way you like.. as roaming network or separate different network.. in either case you can connect and do both backup and internet at the same time.