You should be able to archive it (it's an option when you right click it in Impulse), copy the archive over, and restore it on the new machine. That way you'll get all the registry stuff too so Impulse recognizes it and you can update without reinstalling.

The archive will only work if the operating system on the new PC is the same as the old one. If that is the case, a download and archive operation would need to be done and that will only show up if the game is not already installed. You may be required re-download the game. If this is the case, you may be better off downloading the installer/archive files from Impulse Anywhere http://anywhere.impulsedriven.com/Default.aspx