The bottom line is a 57 is way too big for you. If you can stand over the bike, you need something much smaller like a 53. Even if you sucessfully ride the 57 with the seatpost low, the handlebars are too high.

Sell the bike on eBay and get something that fits you.

By the way, I'm 6'0" with a 33 inch inseam and ride a 56.