Dissapointed with my new speakers

So a couple of weeks ago I replaced my 2 year old Klipsch RB25 bookshelves with a pair of B&W DM603 S2 floorstanders. When I first auditioned them I fell in love with their resolution and clarity however having lived with them for two weeks now, I am very dissapointed in the low-end and to a much lesser extent, the midrange.

On most songs, the bottom end seems very lacking compared to the Klipsch bookshelves and simply pales in comparison to the Klipsch RF82s we have in the living room. In addition the mid-range seems a little over emphasized. I can probably get used to the mid-range however, the lack of low end impact I probably couldn't get used to. I was thinking about adding a subwoofer but a half-decent one would start around $250 and go up from there and the speakers themselves are worth around $450-500. This got me thinking, maybe I should just switch to a different pair of speakers instead of trying to make the current system sound better. What do you guys suggest?

P.S.-I'm in Hawai'i so while I'm open to used speakers, shipping here will usually run about $250+ for floorstanders so I'd only have about $500 for the speakers.