How can I calculate distance based on altitude and glideslope angle?
Since the 1 in 60 rule of thumb yields a solution of 300 feet for every NM from the touchdown point for a 3 degree slope, use 320 feet for a 3.2 degree slope.  So 670ft, gives you a nadgers whisker over 2 nm.

To be a little more precise, 2.09375 nm ($\frac{670}{320}$)