Fiesta MK3 front wing replacement

[JTBUSH]

I have a fairly decent fiesta which my mate is after purchasing. The only thing which needs doing is the near side front wing. Its completely rusted round the arch.

It is obviously spot welded down the top of the inner wing. My question is, how is it joined at the front and at the rear to the bulkhead? What is the best way of replacing this wing? How would you recommend welding the new wing in place seeing as I dont have a spot welder, only an arc and mig welder!