Is there a way to get Baretta back again?

I think I messed up the first time b/c I was really low on HP and I didn't take the quest but now I can't find her again. Where is she?

You missed your chance. Sorry. I hope you have a save point to return to at the beginning of the Marsh. Now that you know where to find her, make sure you load up on health and magica potions in the village (good weapons too) before you accept her mission!