its not as horrendous as it sounds, you should use repair panels, and especially if you are a novice, as those panels are some weird shapes.
now for the good news, there was some of these damper mounts on ebay a little while back, and i don't think they sold (i could be wrong) best bet is to look through our ebay section for the auctions (i posted them in there)
then try to contact the ebay member and see if he still has them and will re-list them.
now for the inner wings, these are not quite as bad a shape, but still not "simple", the area behind the mounts is hollow until you get to the inner wing, so you have a little leeway as to the shape of the inner wing, and can play around making the replacement section 2 or 3 times with no detrimental effects.
the hardest part of the job will be removing the old stuff, as you cut it out you will start to think oh crap what have i done

... but once all the crap is cleaned out it will start to look better.
before you start cutting large areas out, try and find some good reference points on your new panels, and the same points on the original, and measure to an area you are not going to touch, do this a couple of times so that when you have finished cutting away, you have a guide as to where the new shock mounting panel should go, also use the other side for reference too.
as for the welding, if you are not sure on your welding, spot weld it and get someone who knows what they are doing to seem weld the rest, i would not recommend only spot welding it, especially if your an amateur