I’d buy a road bike. I’m not sure there is any need to buy a women-specific model, but the only answer is to have a look around, make a few LBS salesmen work for a living. A friend of mine used her Marin hybrid but once she bought a Trek 1.5 she hardly rode the Marin as the Trek was lighter, faster and handled better, even with panniers.
Size and fit is top priority. I’d argue colour and styling is more important than specification. Why? Because you may well change the drivetrain, wheels etc sooner or later, and they all do the same job, but you won’t change the colour or frame shape.
The main brands compete and churn out terrific bikes. Ones I’d look at first include Giant, Specialized, Boardman but there are lots more besides. You may get a deal on a 2011 model as 2012 bikes will be along soon (if not already).
You could keep the Kona as a commuter/winter/hack bike that you’re not worried about leaving locked up in town, it may be worth more to you than you’d get for it.