Blonde highlights are a good choice for going lighter. It's not as drastic as overall bleaching, and has a less distinctive "root" line while growing out, making touch-ups less necessary.
At home hair coloring should not attempt more then a few shades difference. Go to a beauty supply store and get a color neutralizer so you don't go brassy.
Unfortunately the only way to dye dark hair blond is by going to a salon. I have dark brown hair and tried an at home blond hair dye kit meant for dark hair, and my hair ended up orange.
For all of your hair coloring concerns, I would recommend you visiting a professional in a hair salon. They have the experience necessary for you to take good care of your hair. They could offer you tips of how to do it at home, but they will probably advise you to have them do it.