soundsofthecar on "Forward traffic to new domain?"

I recently mapped the domain from soundsofthecar.com (using GoDaddy) to another hosting site, as I wanted to use the WordPress.org program. However, I want to redirect all of the traffic I'm getting from soundsofthecar.wordpress.com to soundsofthecar.com, but when I type it into the address on WordPress it says it's already mapped...but isn't that the point of having another place for your domain?

I'm confused, can someone shed some light on the subject?

Thanks!