-eba ending is present conditional form.

example: anata ga odoreba tanoshimu. if you dance you'll enjoy it. lol... xD 

I'm not the best authority to answer, but no reply in 6 days, so I'll reply:

Firstly, it's "ganbatte," with a glottal stop, represented in Romaji by double consonant and in kana with a small TSU っ.

This seems like a simple question, and I think I'm right, but hopefully a native Japanese speaker (or someone more Japanese learned than I) might come in here and clarify for us.

But yes, if I'm correct here, the answer to your question is that "ganbaru" means to preservere, keep at it, try one's best, etc. so "ganbatte" means "Go for it / good luck / do your best, etc." and "ganbareba" would be like "if (you) do your best".

-Michael