The facts of this attack are pretty simple although the reasons may not be, you have a password and email address same as has been the case for many many years and someone is looking to bust in by either brute forcing or bypassing the password in some manner, there is a little more to this story than that at "user" level .
Google has a system to check account passwords are valid so its pretty useless at first sight to steal this information on its own unless their code is terribly flawed and allows for incorrect passwords to be accepted as genuine.
I,m not 100% sure what the attackers where after but its likely they simply want information on how the email data is secured in transit as this would allow their government to capture the data in real time for a "man in the middle attack", thats really all I think they are wishing to do as anything else is unlikely to be of enough value for mounting such a public attack, so forget stressing over your passwords etc just ensure you dont keep information (old emails) archived in online email repositories and dont get lazy by using the same pasword for multiple locations or services and let Google do their part in either changing the system or if its flawless trusting it to be as good as they have said it is.
You could of course use other email providers (or many email accounts ) but blind panic is best avoided when reading stories that claim the sky has fallen in or is about to.
