Paypal Standard modification

I would like to change the word "PayPal", next to the radio button, to something else and add a couple of credit card images. I have been unsuccessful in finding where it is in the code. Would appreciate any help.
Thanks...

On mine it's: /catalog/language/en-gb/extension/payment/pp_standard.php

Altered code to give me a little PayPal image looks like this:
<?php
// Text
$_['text_title'] = '<img src="/image/catalog/sample_data/payments/paypal_straight_32px.png" alt="" height="10">';

Remember to refresh cache in Admin/Modifications to see your change.

Many thanks! The path wasn't exactly the same, but your help got me there.