Maybe the Denali Road Bike is your best bet. I see on Amazon that they have a small frame that may fit you (see links below). But you're basically in a really bad price point. Typically a good entry level road bike will cost $700 to $1,000. Having never owned one, I'm not sure how well the Denali will hold up as it racks up the mileage.
One option for you is to go to your local bicycle shop and tell them how much you can spend. Maybe they direct you to a friend or customer they know that is looking to sell a good used road bike. People that are serious about biking upgrade to better / more expensive bikes when they can and may be willing to let their entry level bike go for a few hundred.