MR2 has cancer

So my MR2 has cancer and looking at getting it treated soon before it spreads. I'm not sure if this has lived near the beach most of its life but just wondering if this a common problem on SW20s. I don't want to have to go to the effort and time of trying to find another MR2, and don't really want to try and repair it myself!
 
The first affected area is the drivers side of the roof near the corner between the targa glass and top of the windscreen...and the second is the centre of the roof just behind the middle black bar between the targa tops.
 
Been to a few crash repairers/panel beaters about this and they all have said the windscreen, side quarter windows and back window will have to come out to do the job properly as it has had a poor respray in the past where they have masked off around the windows and painted. So basically the front A pillar, front section of roof between targa and windscreen and back section of roof down to C pillar will have to be resprayed. Quotes have ranged from $650 to $1700 to do this job which should involve cutting the rust out and welding new bits in.
 
Any thoughts?
 

Sorry to hear that mate. Hope they do a good job for you.