Translations:
English - Friedlander's translation is available on Google Books. Its easier to read, and includes helpful footnotes, but it might not be 100% accurate. Pines is a very literal translation, but doesn't help you out. Also, he and Strauss had very strange views about the Rambam.
Hebrew - Ibn Tibbon's is the classic one, though people say he didn't do such a great job. Kapach is supposed to be better, and he has lots of footnotes.
Unless you're really into Judeo-Arabic writings, I don't know if it would be worth the trouble learning the original language.
It does make sense to get some background into Aristotelian philosophy, since that's what Rambam is dealing with. Acording to Rambam, you can't just read one part on its own, since you'll need to compare it to other parts. Even so, you might want to start with a more "exciting" middle section over the homonyms section.