How much did you pay for the Samsung system initially? (could give a rough guide to the quality of those speakers).
Also, do the speaker cables have 'standard' connections at the end? (eg bare wires or banana plugs) or do they have bespoke terminals that connected in to the main unit?
If you particularly like the speakers and they have standard connections on the cables then you could stick with them, but as BigBoss says there's no point paying big bucks for a Receiver if it's several leagues above the speakers (as you won't hear the money you've spent).
In terms of subwoofer, Velodyne and REL are well respected makes so could be a good starting point, and Monitor Audio and B&W are also good in my experience, though I'm guessing your in the States so not sure what brands are available other there.