Someone Accessed my Email from a Foreign Country?!? Please help!

The Recent Activity page (accessible via the Account Info link in our email accounts) shows that two "email application(s)" have accessed my email account from foreign countries I have never been to.  

How can I get more details or information, such as the exact date of access, the IP Address, or the nature of the device / app / operating system that accessed my email?   

Thanks for any help anyone can provide. It's kind of a scary situation.