Where can you get like cute, flowy dresses/tops to wear with leggings? Like the kind Nicole Richie wears!?

Hi! I've been looking EVERYWHERE for flowy short dresses/long tops (the kind Nicole Richie wears with leggings), and I can't find them ANYWHERE!!!!!!!!!! I've tried Lord and Taylor, Nordstrom, Bloomingdales, and even trendier stores like Arden B, H&M, and Express, etc., with no luck! Where would these things be hiding? lol BTW, I won't go into any Target or Kohls, etc. (no poverty stores). Do you have any suggestions???