I am sorry that your laptop was stolen. I feel for you. There are services that will let you track your laptop if it gets stolen. Unfortunately, you have to install a client on the laptop before that happens. This is one example:
http://preyproject.com/It would be difficult at best to track a MAC address over the Internet. Internet routers replace the source and destination MAC address on each packet as they route it. I don't believe that ISPs track this information either. I also doubt that your browser reveals this data, since it would be useless.
You really need an app that can check in from time to time to be able to track a laptop. I am just not aware of any other method. I am hoping that I am wrong though.