While, I don't have it installed on my ThinkPad T40 from 2003, there is a open source software that you install in your next laptop to help you track it down if stolen. That is if you decide to buy another laptop.
Unless the person is just a complete dummy, even the software will not help. Not much you can do except report it and hope it turns up at a local pawn shop somewhere or they recover it in a bust. Even then, unless you have a lot of documentation, or the laptop has not been wiped clean, it will be hard to prove it's yours.
Basically, very sorry for your bad luck, but it's pretty much gone. Take better care of it next time.