PHP is used on the website you specified, but it doesn't necessarily mean that PHP software was used to to create it. Like I said in my first repsonse, you can type PHP up with a text editor.

Now depending on your business package you can get a dedicated server - you wont be sharing your hosting with anybody. Depending on the number of hits to the website (or intend to get) you may need to do some performance tweaking with Apache and the server itself, or if this isn't enough, find a load-balancing solution - but you're going to need more servers.