Tanyah,
sounds like he might be giving you a quotation for a laparoscopy with some endo. removal as that sounds very expensive. I had just an investigative laparoscopy 3 years ago and had limited Private health insurance and had to pay $700 to the hospital, about $200 for the anaesthetist and absolutely nothing to the doctor so $3500 sounds heaps. They probably quote a maximum amount jsut in case but even if that is a maximum it is heaps.
Hopefully some of the girls who have had endo removed will be able to help you out with more accurate cost.