Facebook language

Sipos,
The Login With Facebook text is actually defined in the com_jfbconnect.ini file.

As for the social widgets, if you're Joomla site's language is set to Hungarian, JFBConnect will detect that and try to tell Facebook to translate to that language automatically. It sounds like you're still using the default of en-GB though. I'd recommend you find a Hungarian language pack for Joomla itself, and use that, as it will help translate a lot of things automatically. If you want to stick with en-GB though, you can override JFBConnect's language detection in the Configuration -> FB API tab. In there, you can force the language to something like hu_HU (not sure what it is for Hungary, but there's a link to an XML file on that page you can use to look it up).

Hope that helps,
Alex