The stack and reach are only 6mm different between the 56 and 58 cm frames. At your height 58 would be the correct size so it should be fine unless you have unusual leg/torso proportions. What's your inseam?

99Klein is correct that you should first get your saddle position so that your legs are in the correct position in relation to the pedals. Then evaluate reach.

You can swap the stem first. The bars that come stock on the bike have a 76mm reach and 126mm drop which is already a compact bar. After swapping the stem, if you want further less reach look at Zipp, whose compact/ergo bars have 70mm reach.