You should be able to change the format on your GPS/sonar. It should be in the "setup" menu tab under "position format". Just change the format to the type you need, then input the coordinates directly into the unit.

To change the Position Format setting:
1. Make sure you are in Advanced User Mode, then highlight Position Format onthe Setup menu.2. Use the LEFT or RIGHT 4-WAY Cursor Control keys to change the Position Format.
(dd.ddddd°, dd°mm.mmm', or dd°mm'ss", Default = dd°mm.mmm')