Hi,
Ok so need to be Static IP isn't it? I need to change all the DNS ?
Best practice is to host it somewhere else first. See if it works, using for instance the ip-number or hostname of the temporary location. Update your DNS records, wait a few days to let DNS sync, bring your server down, upgrade your line, bring your server back online, verify that it is there using it's ip-number or hostname change your dns settings (wait a few days again until you see traffic coming in on your own server again) and close down the temporary box.