I must seriously recommend plexiglass... exen if you have to pay someone to use a router and cut it to the shape of your machine.
I tried contact paper to protect mine, and mine was a 50 dollar print from kinkos, when I tried to stick it on the paperit got air bubbles that were impossible to get out, and if you tried to fiz it, it ripped the paper... If you do this method, you must go very slowly and use like a squeegee to make sure there are no air bubbles (ive gotton pretty good at it now, too late as always, lol)
Now, in your case, if you absolutely cannot go plexiglass, then the next best thing would be to get the picture laminated, if you go to college or school, they will surely have a laminater, if not you can pay places to laminate for you (CopyKat or other Kinko type places)
Good luck, let us know how it turns out!