Order your new hosting service.
Upload your website to your new server.
Using the Web Control panel, configure your email settings.

Do this before you cancel your current host.

Contact your domain registrar and modify your nameservers to point to:
ns1.gbcanhost.com
ns2.gbcanhost.com

Now you can cancel your current host account.

After approximately 24-48 hours, your domain should be pointing to gbCanHost.com. Your transfer will, then, be complete.