I am your height and recently bought a 47 cm Trek Pilot 5.0 (carbon frame/Ultegra components) for $700 + shipping on ebay. If you know your size and are willing to buy a used bike, you will get more bang for your buck on craigslist or ebay. If you don't know your size (since that involves more than height and will vary per manufacturer and frame geometry), you are far better off going to a good LBS and being properly fitted.

Good luck!