Can i use a powered subwoofer?

I have a panasonic home theatre system model sa-ht650. The subwoofer that came with it sucks. I was looking to buy a powered subwoofer for it. The problem i am having is there is no sub out jack on the back of my receiver. I do have a spot for a sub that uses a speaker wire. The sub i have now is not powered and there is a single speaker wire running from the sub to the receiver. are there any options that i have. i was looking at this subwoofer to buy. Yamaha YST-SW216 100W Front-Firing Subwoofer. the reason why i ask again is because 2 people said it would work using the front l&r speaker terminals then run the front l&r speakers off the sub. another person said i can not use a powered subwoofer with this theatre system because it was a low end model. if you google the model # sa-ht650 the second link down will give you the complete owners manual. thanks for your help!