Redhead Part 2?

So, I'm not exactly sure what color my hair is right now. After the horrible experience I had with the Vidal Sassoon dye, I Color Oops'd my hair either 2 or 3 times afterwards to make it look better. The length and ends of my hair are a brownish red, which is fine, but the roots are a significantly lighter reddish color.

I've been dealing with it for a few weeks because it honestly isn't that bad, but the thing that bothers me the most is the roots being so much lighter. I'm not completely set on what my plan is next for my hair, but I still really want to be a redhead. I had great vibrant red hair years ago, it was professionally done and cost me a mint. I really don't like going to the salon to get my hair dyed. Yeah, it's more convenient, but I've had so many bad experiences at salons, mostly with haircuts, that I try to avoid them. Plus, I think its fun to dye your own hair.

Anyways, there are several Garnier Nutrisse box dyes specifically made for naturally dark hair. Most of them are nice reds too. This one is the one I'm seriously considering, the results that I've seen have been a beautiful bright red shade:

Later this week I have 2 days off in a row. I think that's when I'll go for it!