roof repairs cost

I am currently looking to buy my first car and am in love with the vw eos. I have been dreaming of owning this car for years. In my country you can find a used eos starting from 5000€ but i read i should stay away from pre 2008 eos due to roof leaks, so 2009+ eos with decent mileage start from...

A while back an Eos owner here used the phrase "my hydraulic pump took a swim". Seems this happened to me. We had some unusually severe weather here and water got into my car, damaging a few things. I'm looking for advice / tips on how to proceed. The dealer hasn't completed a full diagnosis...