What made you purchase the bike in the first place? That frame is way too big for you. Not only is it too tall, the F-Series have an aggressive top tube. A 52 cm would probably fit ou perfectly. Also, 5 year old Dura Ace is still good. We are talking about the 7800 group which (in my opinion) is one of the best Dura Ace groups ever made (second only to the 8 speed 7400 group). This is a tough call. Selling the frame/fork and putting those components on another frame sounds senticing, but so does selling it and buying a new bike that fits you. You won't get Dura Ace but you'll still get a bike that fits you.