reading the position of a switch using a microcontroller
If you can, replace the switch with a DPDT switch, and use the second pole to feed a digital input pin.  In this case the second pole could be used to switch +5V or groud to the digital device input. 

If you can not, you could use an instrumentation amp to sense the current through one or both resistors, setting the gain so that the output is a logic high level when the motor is drawing current through the resistor and is a logic low if not.  (Being careful not to overdrive the digital input level.)