How to Change Delivery time USPS 1.5.6.1

I am looking for a way to change in USPS extension that comes with Opencart 1.5.6.1

From:
Priority Mail 3-Day
Change to:
Priority Mail 3-5Days

Is there any way to do that?

Thank you!

Edit the associated language file...done.

catalog\language\english\shipping\usps.php

tacobandito wrote:Edit the associated language file...done.

catalog\language\english\shipping\usps.php

This is all I can Edit:

<?php
// Text
$_['text_title'] = 'United States Postal Service';
$_['text_weight'] = 'Weight:';
$_['text_eta'] = 'Estimated Time:';
?>

There are no preset times, I think it takes it from USPS server. Any other ideas?