Without knowing what kind of riding you'll be doing and what you're looking for in a bike, I'll just throw out some general suggestions.
I'm assuming you'll be doing easy trails and/or paved roads. I'd recommend going with a hardtail (front suspension only). Specialized has a women-specific model called the Myka. I'd recommend going with at least the Disc model, or the Sport Disc, which is right under your price range. Take a gander at one at your local shop. Make sure you're fitted properly.
You will also notice that this bike also comes in a 29" wheel size. It's been gaining quite a bit of popularity over the last several years. I ride one, but my wife, who is 5'6", doesn't like them. She prefers her 26" wheels. So they're not for everyone. You will have to ride a few and decide.
Also, remember to take into consideration that you'll need extra money for a helmet, gloves and bike shorts. Hope that helps.