I think you need to evaluate and plan for replacing the floor/toeboard and the lower cowl, both inner and outer. Does the DS look the same? This is a very common problem with all of the AD series. There will be good help here to guide your decision and advice along the way. My pictures on similar repairs can be found here.
https://www.flickr.com/photos/advance-design_parts_co/8129102309/in/album-72157631867396207/