These are the typical areas where these cars have rust.The only sure way to repair it is to remove the window.Then all the rust can be grounded out and new metal added,maybe lead soldering.These are great cars if you can stop the rust.I have 2 coupes. My '80 is rusty may become a parts car. My '81 has no rust and perfect interior.Most volvo guys give these car a bad rap.But the coupe will be a collector car in the near future.You may want talk to a good body welder,not someone who does insurance collision work.good luck.
Nelson