Well, for starters you need some configuration information about the domain you purchased, and the IP address you believe you have.
First, purchasing a domain does not necessarily come with an IP address, or set of IP addresses, unless you buy your domain from your ISP. What it does provide is the ability to point the domain you purchased to a DNS Server. You can either host the DNS server yourself, or have someone else provide it, but in the latter case, it is rare to find a provider that will give you enough control for anything more than the most basic DNS options.
Once you have pointed the domain to a DNS server, you then configure that DNS server to assign an IP address to each system in the domain (e.g.,
www.smith.com, or mail.smith.com). In your case, it seems that you would want to assign
www.smith.com (or the purchased domain), to the existing IP address on the existing server. Once that is done, anyone who types in
www.smith.com will be given the IP address of your existing server.
Please keep in mind there is a whole host of security issues related to this scenario that have not even been approached. The web server should be protected behind a firewall, and you should follow security best-practices for locking down any kind of IIS server you wish to make public. But those are topics for another thread.
For now, what you need is to determine where your DNS server is for the domain your purchased, find out how to configure it (or request changes), and then decide where you really want to publish your site (or how to protect your existing server if you keep it where it is).
Good Luck
Elohir
Unsolved 
