I feel for you with this, I had a similar problem with the pollen filter filling up on my Audi Cabriolet and over the course of 6 weeks when the car was parked up in all weathers, it just kept soaking in and I didn't know!
I had to strip the whole interior out of the car, carpets, dash, seats, everything in order to dehumidify the car and carpets, plug the leak, replace the pollen filter and reseal the scuttle panel, dry, test and reassemble.
Whole process took me several weeks, hours here and there.
Once its done its done though - I would recommend if you can to try and do some of the legwork yourself and you will save a LOT of labour money!
Getting to this stage took about 4 hours before the dash even came out (and this is on a 20 year old cabriolet)
