It does seem as though you're trying to fill a fairly large room with quite a small speaker.

If you do start looking at new speakers, the Energy Veritas 2.2 is a pretty amazing bookshelf speaker as well. It has an msrp of $1500, but occasionally you can find a pair as low as $800.

Though, having said that, I ended up buying a pair of M60ti's instead of the Veritas. Both had their +'s and -'s, but in the end the soundstage and detail of the M60's won me over.