IT Employment

I have come into an environment that needs to be changed, and though I do have experience setting up Win2000 Networks, this would be a new challenge for me.
Currently, the domain, which consists of 3 servers is named in the following manner: domain.domain.com
Also, the AD server is not stable, and I want to basically take it offline. The other 2 servers are a Citrix Server, and a SQL server. For the time being, what I would like to do is actually create a new domain, with the proper name structure (domain.com) and have the SQL server be my main AD server....just not sure how to really go about this...any help would or point in the right direction would be greatly appreciated.

Thanks