To those who are still receiving the emails about someone trying to access your account, PLEASE, PLEASE, go to Google play and download the free app Network Info II. Once you launch it touch IP at the top of the screen and it will obtain your external IP address . This is the IP address used by your internet service provider. You will most likely find that this is the same IP address trying to access your account.
Googling 'My IP' from your phone/PC will show you it too, at the top of the results.
Also worth noting is that your wireless router and your mobile data connection have different IP addresses.