I have overwritten my file( a webdocument with extention .php) with the old one, I tried to access the cached version from google and I found the one i.e,http://webcache.googleusercontent.com/search?q=cache:http://minnesotataxiandcarservice.com/testimonials.php&strip=0 but I am looking for a way to recover it, when I tried to view its source code all I can see is the html scrips only as the php part is not visible. Now I am looking for a way to retrive a whole document with original contents including the php coding. If there is any way to do so please mention it.
You can't.
Next time, you should be using a version control system, like Git