The box should have its serial number on it, and you can also get the serial number from a computer's iTunes backup : Find the serial number of your Apple product - Apple Support
Unless you had Settings > iCloud > Find My iPad enabled on it then there isn't any way to try and locate it. And that will only work if it's connected to a network and hasn't already been wiped and/or Find My iPad disabled on it.
I assume that you reported it to the police. You should also change your iTunes account password, your email account passwords, and any passwords that you'd stored on websites/emails/notes etc., and if it was a cellular model also contact your carrier.