Ardell Red Gold Corrector - help

A couple months ago I tried to dye my hair a little lighter, from a medium brown to a light brown. . . but now my hair has horrible brassy tones. I'm not one to exaggerate or overanalyze either; my hair looks bright orange in the sunlight. The ladies at Sally's recommended the Ardell Red Gold Corrector, which adds violet tones, and said I could add it to my leave in conditioner and let it soak into my hair, which I did for quite a while. I added 30 drops and kept it in for about an hour, I believe.

So my question is. . . what do I do now? I had a bit of an idea, but it might be stupid so I don't want to just go try it and couldn't find much info on it. I was thinking I could mix the red gold corrector with my conditioner as usual but also add a bit of developer to help open up my hair a bit? If this is a bad idea, I suppose I could just add more corrector and try again.

I'm also open to other suggestions altogether! Sorry it's so long and thank you!