Other than the image in the center it looks like you are dealing with all geometric shapes with a few small leaves added.
The cross itself and the geometrics can be created with vector lines and 3 point arcs and there are many 3d images of leaves out there.
I would just draw the boundaries of the cross and work on creating it from scratch from there. A grid overlay will go a long way in helping you keep the proportions close to original.
I've seen similar pieces offered as ready to cut files from some of the eastern European designers on E-Bay and the Artcam Forum.