im relatively new to this whole surround sound thing, so i apoligize in advance for any stupid things i say :)
i currently have a 5.1 speaker set-up from yamaha, and i was wondering, since my reciever has two main speaker outputs (A, and B) could i possibly add two more speakers to the setup. I've already connected some old stereo speakers, and it's worked, but where would be the best placement for these new speakers be?

right now, i have two main speakers about 2 feet from either side of the TV, being supported on shelves. A subwoofer next to the right main speaker, and two rear speakers about 6.5 feet from the ground off to the side behind me at different distances (about a metre away). I guess my main question is would it be wise to add the two new speakers, and if so, where should the placement be? and also, what is the best way to place my current system?

Oh, and if anyone has an extra universal remote for an HTR-5450 yamaha Reviever, please email me at blinkythepig@hotmail.com

thanks alot guys, and im sorry for the vaugeness of the question :)