If the starter works it's fine,I'm guessing everything in the car works untill you run out of juice due to the alternator not charging?
Those things are so simple it is either a bad alternator or something in the field wiring (small two prong plug) as far as I remember the big red 10ga wire goes to the starter and then on to the fuse box and starter switch,I'm not positive about the field wires but I think one is hot ahd the other ground,the regulator is built in to the alternator,if it were me I'd slap another alternator on there and see what happens and if that don't fix it start looking into the wiring,Good Luck,KillerDave