OK, that looks repairable. Is the rust damage contained to the windshield channel? How is the top and face of the dash? If it OK, I would not replace the dashboard. I had the same issue on my 1967 Impala SS. My window channel was filled with bondo. The top and face of the dash was undamaged. I ground out all of bondo to expose all of the damage, which was 2/3 of the windshield channel was GONE. I took it to my body guy and he said "just put Metal-All (a body filler) in there....you will never see it". I said "No". I wanted it fixed it right with metal. So he fabricated the ENTIRE window channel in metal, from A-pillar to A-pillar. It was expensive, but it came out PERFECT.
