Go to the View menu > Background Bitmap > Place
Use the control point curve tool to trace the inside of the band
then use the sweep feature .
or use the Extrudecrv command
When your done use View > Background Bitmap and select "Hide" to hide the image or "Remove" if you want to completely remove the image.
I would use a cut tool for the hole in the band, or make sure it is in the extrude curve, for the free loops (free rings) i would use a separate sweep feature. might also build the clasp in parts and add it in using Extrudecrv