Since the online vendor only offers the Motobecane Gran Turismo on sizes 54 and 58cm, if I were you I'd go with the 54. You're in between sizes 54 and 56 based on the based on the dimensions you provided on your other thread. 56 would be optimal, but you'll be fine on the 54cm frame as well. A 58cm would be a complete overkill and I don't believe you're going to be comfortable with a top tube so high and long. The differences with the 54cm frame will be so minor that you can play around with the rest of the components (stem, seat position) to get you properly fitted. You're getting a good deal on that bike and the savings can translate into spending a few extra bucks on the components you need to make you feel comfortable on it. If it makes you feel more at ease before unloading your hard-earned cash, call up the online vendor on Monday and ask them what they think based on their experience. Ride a few 54 and 56cm bikes at a bike shop tomorrow if they're open where you live. BTW, what size frame do you ride now?