question regarding domain names

I'm hosting my domain with godaddy, and I used the NS you gave me and filled that in with go daddy.com (ns1.siterollout.co.uk and ns2.siterollout.co.uk) as my ns. I don't know much about domain names, but will doing this apply my domain name to my site?

If not I'd appreciate it if you could tell me how to apply my domain to my site.

These forums are generally not for the end users. Your better off contacting your hosting providers about any issues you might be having.
My guess would be: http://www.siterollout.net/support/

As long as those are the proper nameservers, you configured your domain to use them with godaddy, and the domain has been added to your DirectAdmin account with your hosting provider, it should start working within 72 hours.