you can't easily create 3d from 2 identical pieces of footage - the shots need to be from two different perspectives - like when we see things from our own eyes that are set apart.
you would have to cut out parts of the image and move them around in the frame to create depth. or perhaps find a plugin that simulates 3D
with regards to 3d footage in FCP - there are lots of plugins for final cut for editing in 3D