hi, i'm not aware of any current developments towards that direction but i'd agree that this would be a welcome addition. there's one bug on file for that (bug 638905), which you could vote for, but which hasn't seen some activity in a while...

if you are concerned about security online you should probably also update firefox to the latest version and update your plugins as soon as possible, since you're apparently using outdated versions which are actively exploited on the web already!

I really think Firefox needs this. Two factor authentication is becoming standard now. My accounts at financial institutions, Google, Microsoft, Apple, and even Steam all use it. With the public awareness of hacking and identity theft, a platform that asks to remember passwords and stores them "on the cloud" so we can access them from any device using the Firefox browser really needs this to make us feel comfortable.