Surround sound troubles..

[locodcdude]

Okay so I have a Yamaha surround sound 5.1 system I just bought. I have an A/V receiver I purchased on ebay. It has 6 spots to hook up speakers. 4 front speakers, (Set A speakers, and set B speakers.) and 2 spots for 2 rear speakers. I hook up my 2 stereo speakers to the A spots. My 2 Front speakers to the B spots. and my rear speakers go to the rear terminals. I have my subwoofer and center channel just chillin there not hooked up.. I'm not sure what to do.. I have a "surround sound receiver" and it has surround mode, but no place to hook up a center channel and a subwoofer.

Without buying a new receiver, what should I do?
Thank's guys!

[VK_Electronic]

for the sub

check it - the older [better] subs often had a facility for being driven from the amp

else look for a commercial add-on

else make one! maybe easiest to have a resistor divider, adder, low-pass filter, then mono amp