its this 5.1 surround package, it came with a decent sub, but the small speakers are weak and the center channel is terrible

the link is to specs on my receiver, i know its nothing fancy<ul><li><a href="http://www.yamaha.com/cgi-win/webcgi.exe/Specs/?gAVR00010HTR-5140">http://www.yamaha.com/cgi-win/webcgi.exe/Specs/?gAVR00010HTR-5140</a></li></ul>

Avoid the Bose VCS10 whatever you do - it's horrible. Not all Bose is ghastly, but this piece is just pathetic.
As you are using sats, timbre matching isn't imperative.<ul><li><a href="http://cgi.ebay.com/JBL-Northridge-2-Way-Dual-5-Inch-Center-Channel-Speaker_W0QQitemZ160134973449QQihZ006QQcategoryZ14 992QQrdZ1QQcmdZViewItem">Try this - it's easy to drive and should work well enough with your gear.</a></li></ul>