According to the S&T help file, you don't need to do any calculations. The find box understands degrees, minutes, seconds:
DMS coordinates can be entered in any of the following ways, where D is a single letter that indicates direction (N for north, S for south, E for east, or W for west):
dd.mm.ss.sD
dd:mm:ss.sD
dd mm ss.sD
dd°mm'ss.s"D
Again, this is Streets and Trips. I don't know if Autoroute is different.
Also, in Streets and Trips you can go to Tools -> Options -> Settings and change the display from DMS to decimal degrees.
Rick