Take a new battery...
or one from another car. At least it will take you home. You don't mention what model but, probably the brushes of your voltage regulator are bad. Just take a screw driver (to remove the regulator) to remove a couple of screws from the back of alternator. The battery, you can remove even with plyers. As far as the belt, just check if it is tight. If it is not, that may be your problem.Tools for the belt? Depends on the model...
Good luck! :p