Moving servers without much interrupt?

I might want to move. I want to have less interrupt in my service. I use now: web, mail as one server and a database server on the internal LAN The distance is far, and involves several days customs. To overcome a periode of two weeks, I wanted to setup ONE server on the new location, which does everything, web, mail, database. The DNS is now also on the web server. As first I want to move the DNS to the other place, but with the old IP addresses for web and mail. What and how do I go next? bye Ronald Wiplinger