Hi funkyspunkymonky!!
Firstly your link
www.sierradisplay.com, is not available to me. The site
http://www.sierra-display.com/ is viewable.
Check out your hosting and IP addresses.
I have firewall and antivirus which may affect what I can view but at the end of the day your old site is still live so you really need to make sure that your new address works before worrying about being found.
As above once live put in a redirect but your old address is probably better than the new one.
Just a thought, hope it helps