Color wont stay!

I have dark brown hair, naturally. I havent seen my real color in almost six years. I had a perm, and really beautiful blonde hair for three years. October of last year, I decided that I no longer want the perm and had my hair straightened. Afterwards, they had to cut off 5 inches of my hair, which was fine. I now hate the blonde and want a darker more golden brown color, not too dark. I have been dying my hair darker a shade at a time and it looks fabulous for the first three days then the color comes out. I have been using a level 3 permanent color, which should not do that I believe. My hair is just starting to grow long again and cutting it is out of the question, so...How can I get the new color to stick without "removing" the color in it now and without getting it cut. I cant afford to go to the salon anymore. I need an at-home solution here. The color mostly comes out of the end, not the root. Help!