domain mapping issue

Hey everyone, I love wordpress but I am having an issue trying to redirect a new domain I bought to one of my existing blogs on my multisite network. I installed sunrise.php to wp-content, uncommented sunrise on in the wp-config, and installed domainmapping.php to mu-plugins. when I go in my super admin tools I dont see any option to click domain or domain mapping. If I go down to 'tools' i can then click domain mapping. then when i enter my new domain it tells me ''IP not set up by admin yet''. how do i assign the IP address? or is there something else i am missing?

the current site is

i purchased the domain and would like that domain to redirect to my current blog.

any help is much appreciated.