Damn rust

[Ivan141]

Grind off all the rust, especially clean the swiss-cheese like bit around the hole. Dont forget that panels have 2 sides, or it will just start rusting from the back again.
Once it's cleaned immediately apply a rust treatment (rust converter), because blank metal will start oxidating the second it's clean. Then apply filler and a good coat of acid primer.

This is just the amateur botch-job way of doing things, but if you had the cash to have this done professionally you wouldnt be asking us now would you.