I don't think you're really going to improve on your present speakers in bass tightness while still maintaining the positive aspects of your Renaissance Audio speakers for the price constraints you have. With the AE's and Ascends you may get the same sound as the Polks, tight bass, harsh treble, which is the typical failing in this price range, albeit the used AE's would be my preference over the Ascends.
However, we had a similar thread a few spots down, "Best floorstander under $1K" and some of the cheaper candidates from that may do, namely Maggie MMG at $600 and Energy C500 at $400, or Wharfedale Diamond 9.6 and Paradigm Reference Monitor 7 if you can find them on sale. In the end you may find your RA's are not so bad after all, maybe room treatment or speaker placement can fix what their lacking enough to live with until you're re-employed.
