If you're looking for a road bike, you might want to try a men's road bike vs. the wsd's (women specific). I just went through the whole process of buying my first bike, and I learned that the wsd's are geared towards the avg. woman who has longer legs and a shorter torso. You sound like me (I'm 5'2") and have a longer torso and shorter legs.

I ended up spending $500 for a new 2006 Trek 1000. Yes, it's an older model, but it's plenty of bike for me as a new rider. I know it's a little more than your budget, but there are deals to be found (I believe this bike was about $800 when it first came out). The benefit of buying new vs. used is warranty and LBS help. I also got 1 yr of routine maintenance on my bike, which equates to about 1 tune-up ($60) and any other fine-tuning I need.