very sorry to hear about your misfortune.
this issue has turned up before: www.iwc.com/forum/en/discussion/30471. i think generally the (very good) advice is to:
[b] "Immediately get your police report number and inform IWC in Schaffhausen ASAP. Without the police report they can't help. They will send you (electronicallly) a form to complete so that they are able to help you to their maximum ability. I can assure you they do all they can. IWC does internally register approved (via official police report) stolen and lost watches."
"My suggestion is that our forum friend should make a list and then send to IWC, the local police, all dealers within a radius of where this occurred and major second-hand sellers in the area. I also would suggest visiting the local vintage watch fairs for a few months (there are a few near I believe). These watches will appear again"
"write IWC at info@iwc.com. They will keep a record and contact you if the watch comes in for service. You will need then to have the police verify your report." [/b]