Bright red hair from brown box dye?

So basically I've had bright red hair for 4 years (no bleach besides whats in the product) and a few weeks ago I was "over it" and decided to put a dark brown box dye over the red. Now I hate it and am trying to get back to red ASAP. I use Loreal hicolor in red, and I know if I put it over this brown it'll still be a darker color than what I had before. I refuse to actually bleach my hair but I will use a color stripper. So could anyone recommend me something I can get at walmart or offer any advice? hair before & after here