Ouch. Ok...
There are two things: the mounting clamp has slipped and the dérailleur cage is bent, quite badly. Unless you are on a really tight budget you should probably get a new one (last year's model or before). Bending back requires: patience, a clue how the dérailleur cage should look like, patience, skill, patience. And as the guy in charge of the workshop in my flying club used to say: you can not unbend metal. There will remain a kink and the structure will be weakened. The chain might just catch the edge and bend the cage again.
Looking at the pics again, it might be done. The bends seem to be not too sharp (for the outer plate)
- Undo screw for the cable
- Remove dérailleur from frame (open clamp screw)
- Open the screw that holds the two cage plates together (to free chain and to work on inner and outer plate separately)
- Using where the inner plate is fixed to the parallelogram, try straightening the inner plate first
(and for me the final step would be: after some hours decide to get a new one, as they are so cheap when getting an older model online, in Germany there's shop.cnc-bike.de who do have old stuff, the FDs start at 5 EUR (7 USD?)).