stepper motor question

Hello list.
.
I am looking for an electronic circuit that will allow me to read a
voltage and then based on that voltage drive a motor in one direction to
raise a load or the other to lower a load. Or leave the motor alone if
the voltage is with in the range. I was told of a window compactor and I
see how it would work . A window comparitor was posted in the
cad-cam-dro files section and I did save it here someplace but it was
using a standard motor which will not work for this application because
a standard motor will not stop instantly and is not made to be turned
off and on several times a min and thus a stepper motor would be a
better choice. Can someone here point me in the correct direction for a
new or modified circuit to do the above function?

Thanks
Stan