Page 1 of 5.1 Decoder needed

I have a setup where my DVD Player is separate with a 5.1 decoder (this allows me to plugin PC, Sky+ , DVD as inputs and then the subwoofer powers this to the other 5 satellite speakers {I think}).
My decoder is beginning to go after a just over a year (typical). The subwoofer still works fine and the satellite speakers are fantastic (look just like the Bose 5.1 Surround 2 part speakers - although most probably a cheap copy !) But I`m needing a new decoder.

Can anyone suggest a cheap alternative ??