Answer:
That's pretty simple actually. You can't. Since you don't have any internet (That's what you stated in the question, that there's no source of internet ).
You can find out if the internet is available in your area and purchase it. You can not use a dial up connection for the PS3. You also can not use anything that will connect to your USB plug as that also will not allow a PS3 internet connection. You need a broadband connection with ethernet cable to your PS3 or a WiFi connection from your router or modem.