is color stripping necessay to go from blonde to dark brown?-ASAP!

I have naturally dark brown hair that is currently dyed blond. Would it be necessary to have the color stripped before it's dyed back or can the brown just be dyed over the blonde? I'm not sure what I should do because the salon I go to doesn't do color stripping & I'm afraid they'll want to bleach out my hair before dying it back to its original color. Because my hair is a darker blonde on the top than on the ends, I don't know if the color will come out even if its just dyed. Is stipping more damaging? Please help because salons are scarce & overpriced where I live. Every time I've gotten my hair colored at one they ruin it beyond belief. As the color develops they stand there & say "Well, It should come out like you want" when of course it doesn't. PLEASE HELP!

Jennifer and Amber,1) Jennifer, find a different colorist. My previous one had me convinced that color application was an arbitrary thing, and that there was never any good way to ensure consistent, well-matched results. She implied that one had to live with whatever "came up." My present colorist proved her wrong.2) Amber, you were lucky.As I've mentioned in other posts, I had bleached platinum hair that I dyed dark red in February. My natural color is light brown. When I made the choice to go red, I was concerned about getting even coverage. Some parts of my hair were blonder than others, and my roots were dark.This is what I experienced:1) Because double-processed hair is so porous, I had to have it "filled" before the actual color was applied. It creates a more even "canvas" and gives your color something to "cling to." (Remember, most of your hair's pigment has been stripped.) In my case, they filled with a true red. They would probably fill you with brown.(NOTE: If I had skipped this step and tried a red out of a box, my hair would have turned pink! Bleached hair is nothing to fool with.)2) Then they applied the permanent color (in dark red, the color I wanted). This took better on the virgin hair at my roots.3) They went over this with a semi-permanent color called Colorance--also in dark red. (It's from the Goldwell line and is kind of like a cellophane.)4) It looked great, but it began fading very quickly. The old blonde hair just couldn't hang on to the color as well as my healthy hair. So a few weeks later, I had two or three different shades of red on my head.5) HOWEVER, every time I got my hair retouched, the color looked better and lasted longer. Six visits later, you can no longer see any variance in my hair, and the red stays true between appointments. Each time I go, they apply the permanent color to my roots and then, in the last 10 minutes, comb it through the rest of my hair to blend and cover. Then they do the semi-permanent. Once the old blonde hair has all been cut off, I won't need the semi-permanent anymore.6) Color-enhancing shampoos and conditioner by ARTec or Aveda can help hide any fading and unevenness between appointments.7) Don't try this at home.All best, Ally