Does your phone have Mp3? and can connect onto the computer VIA usb port
?
If u can then. Get the song you like and the part that you want.
To do that
You go on Windows' movie maker.
Click Files, Import media items. and choose your fav song.
Now you put it down on the time line and u can shorten it and get it to your favourite part which you would like to become your ring tone.
Publish it as an mp3/wma file.
Then put it in your phone and set it as ring tone.
U dont even need the internet for this. at all