Patt,
In the list, your PSW10 is the one you should be worried about. There is no way it will do justice to that room size. IMO, return it if possible and get an SVS, Hsu Research, Rhythmic, Outlaw Audio sub.
I'm not familiar with the Monitor line and cannot comment on the center speaker options.
Either of the receivers can drive the speakers. The marginal difference in power between them will be inaudible. Pick whichever has the features you actually see yourself using.