You can install our site as a web app on your iOS device by utilizing the Add to Home Screen feature in Safari. Please see this thread for more details on this.
Note: This feature may not be available in some browsers.
You can order through the Tesla Parts Catalog using your app with the part number. See Parts Catalog for more info, but I think the minimum quantity is 50. Your local Tesla store may have some as well, as they likely need them for when they screw up.