can i block my ipad that was stolen last night?

Not block. If you enabled and installed 'Find my....' software you can set it to be remotely wiped if it gets on the internet.

There is no tracking or blocking stuff beyond that.

What I'd suggest is make a report with the police. Then change any and every password you ever used on the device, iTunes, e-mail, anything.

The 'find my' software is really meant to be more of a 'where did I set it down' than a recovery app and anyone that knows what they're doing can defeat it in a matter of minutes.

If you make the police report, complete with the serial number (You can recover this from iTunes) then if it ever turns up you can get it back.

Did you setup and activate the free "Find my iPad" service on it, before it was stolen?

If so, you may be able to lock it, locate it, send it a message, or even wipe it at http://icloud.com/