Wheel size: 650 to 700
Sorry, that frame will not take larger wheels.

Triathlon/aero bikes have minimal clearance between frame/fork and wheels which do not even allow larger tires in some cases. Additionally, bikes equipped with rim brakes will not take different size wheels because the brakes will not line up with the rims.

The assertion about smaller bikes needing smaller wheels to maintain geometry is true. 

An XS size sounds too small for someone 167cm (5'4 1/2"). As you bought it used you may want to consider selling it and looking for a bike the next size up.