To restore rust areas before selling?

[screwloose]

Hi, my O/H has a mk2 1.8i on a W plate with a full mazda service history on 100k miles.
The car has rust in the usual places : sills pretty rotten and rust around the A pillars.
Question is whether its worth getting these areas restored before selling? With the likely value in mind is it worth the cost of repair. I understand we will likely not get all our money back from the cost of the repair but does it make any financial sense?
What is the likely repair cost?

Thanks