CSC will still repair imported sets dont they? You'll just have to pay for the repairs. I'm sure they'll take it in.
Anyway, if I may go slightly off topic... I was quite disappointed with CSC today, I sent my 85mm in for calibration due to front focusing issue, and it was not fixed, infact I felt that my focusing got slightly worse... I had 2 hunting experience for the first time today... on an 85mm F1.8 USM.. =(
That's like calling a doctor and asking for X-Ray on the phone. Without proper inspection nobody can give you a reliable quote. Go to CSC and at least get a proper assessment of the damage. Then you can decide whether you give it to CSC or any other shop.
Worst case you get quoted cheaply and then you'll wait 8 weeks and pay 80% of original price.