Contact Acer.
Have you installed any tracking software on it? I guess not, since you wouldn't ask that question.
Apart from reporting it to the police, you can do some basic investigation, for example if you have Gmail account, and if you were logged in the browser, you can check the last 5 IP addresses that were used, hoping that a clueless thief launches the browser, and goes to your gmail account.
http://support.google.com/mail/bin/answer.py?hl=en&answer=45938#0
It's a lot of if-s, I have to admit, and again, an IP address is not much, but it's something to tell the police.