Stepper motor with adjustable pause controlled by potentiometer

I would at least recommend a driver with an DRV8825 chip.

You don't need that much ( if you have only one Stepper ).
Your stepper needs 1.7A+3V+2 = 10.1W in standstill. A power source with 12v/2A ( =24W ) should be sufficent. Don't forget the bulk capacitor at the power input of the driver.