Dragonblood: Yes, you can. You can bullet the caster with a chance to miss, or you can cast Magic missile and be certain to hit for the same amount of damage ...
Admiral: I have your character using a composite longbow, which has a range increment of 165 ft. Therefore, lobbing arrows at either caster or the archer should be no problem from where you are. I just need to know who your target will be for the next round ...
KoD: Your intention(s)? To finish off, subdue, or monitor?
I need both these bits of info for an update (unless you want me to make the decidions, heh-heh!)