I can't translate at all, but I've got to drop my 2 cents on the following:
The previous translator is busy with work (and isn't a big fan of hers so isn't that hyped up about it) and can't continue with the project.
Regardless of whether he's a big fan of hers or not, the previous translator you had should finish what he started. You don't just bail out of a project in the middle of it. He says he's busy with work? What, is he working 24/7 or something? He can't spare 30 min a night to translate a few minutes? That's just bullshit. In the real world bailing out of a project in the middle of it is unacceptable; it would get you fired. If you're going to commit to do a project like this, be man enough and have the fuckin' balls to finish what you started.
Personally, I say if you can find a replacement translator who's willing to commit to do the whole thing, start of from scratch. Throw away the translation that the old translator did (if he's not a fan of her's he probably did them half-assed to begin with) and stick with the new translator. When it comes time to do the credits, the old translator should NOT be included in them since he wasn't willing to truly put forth the time and effort to properly do his job.