I want to add A .com Domain ... an admin can help me ? my account name is sergyu and i want this domain www.ultimaconfruntare.com for this hosting account ultimaconfruntare.zxq.net Thanks

Did you already buy the Domain? If not you need to go buy the domain from a domain host like www.godaddy.com Or any others.

the domain is mine

Ok then Log In To your domain for whatever Registar You bought it from. Then Add the nameservers that zymic gives you to them, and Add your domain as a custom domain through the Control Panel.