Funbare is just the imperative form of funbaru. I only had to google "funbare japanese" to get a page with a conjugation chart etc.
"to brace one's legs, to straddle, to stand firm, to plant oneself (somewhere), to hold out, to persist"
Ganbare is also the imperative form of ganbaru (you're telling someone to ganbaru).
Edit: Thanks for the translation, btw.