Inner Fender Replacement
How bad is the damage? How did it get damaged? It might not be the only piece that has damage. I used to be a body man and I have never seen a just an innfer fender damage unless something came up from under the car and in that case you would have suspension and / or frame damage. If it was a frontal collision then you could have damage to the raditor support, inner fender, frame rails, suspension and even possibly firewall damage. We need to know what how this happened to access what the out come would be.
To remove the inner fender then you have remove the spot welds from the firewall / door pillar and remove the spot welds from the raditor support. You also need to know what the correct dimentions are, if not then nothing would line up correctly when putting everything back together.
As far as I know there are no aftermarket companies that make inner fenders. Your best best would be find someone that is parting out a Duster and try to find an inner fender from that.
Hope that helps.
BTW I find doing body work a lot easier then say rebuilding an engine which I find intimidating. LOL!!!