Tracking IP address of last facebook login

Hello,

So my mate's computer was stolen. We've worked out that his facebook has automatic login when a browser is opened, so if we can trace the IP address where it was last logged in then theoretically we will be able to locate his computer. I know how to find the IP on emails and websites, but can't quite figure out how to do it in this case. Can anyone tell me how to trace the IP address of the last few logins to Facebook?

Thanks!