The K179 is an old constant-voltage design for driving unipolar stepper motors, and its step pulse generation is fixed frequency. The first step to getting higher speeds is to ramp up the speed gradually instead of trying to go instantly from standstill to full speed. To do this, set the switch or jumper on the K179 to EXT and feed in a pulse train with a gradually increasing frequency, as o_lampe says. You can generate this on an Arduino.
To get really high speeds, you will also need to use a constant current stepper motor driver instead of the constant-voltage K179.
To get really high speeds, you will also need to use a constant current stepper motor driver instead of the constant-voltage K179.