Yes, Ken, as sushi mentions I use and recommend a small vertical speaker(such as the M2) for the center channel which is as similar to the main speakers as possible(unless the mains fall into the POS category, as you indicate). To anchor the center channel material as closely to the TV screen as possible the speaker would be better positioned directly above or below the screen, rather than off to the side.
However, I assume that you've noticed that your 2 present speakers form a "phantom" center speaker when they reproduce center channel material. It may be better to stay with that at least temporarily and instead of a center speaker to get 2 surrounds, which should add more to your sound than a center would(I hope that she doesn't think surrounds are ugly).
