Changing ductwork from floor vents to attic vents
I recently purchased a 1200 sq ft ranch on a slab that was built in the early 60s. The ductwork is in the floor and after all the rain recently we found out that the ducts are broken and are taking in water. We can thank the previous home owner for NOT disclosing the house has flooding issues for this. I noticed that the house doesn't really heat right but I just figured since the system is kind of old that came with the territory. It is a gas furnace.
So now we need to fix this issue ASAP. My first impression is to install vents in the attic and seal the vents in the floor, but I am not really sure where to go on this one.
So here are my questions:
1) Is there a better solution than the one I gave? I do not want to rip up the floors.
2) Any idea how much this would cost? I would have about 9 or ten vents installed in the attic and the attic is very accessable.