Pass values to external class

Good day,
               I want to add a payment gateway to my project. For that, the payment gateway guys provided their code, now I want to pass some values from my controller to that file (Attached). The problem is the whole file is a class. I cant create my own function in it.

Code:

class NetworkonlieBitmapPaymentIntegration
{
$networkOnlineArray = array('Network_Online_setting' => array(
'MKEY'    => "REDACTED",
'MID'     => 'REDACTED',                                                              
'amount' => '1000',
'name' => 'ADCB',
'currency' => 'PHP',            
));
}
$networkOnlineObject = new NetworkonlieBitmapPaymentIntegration($networkOnlineArray);

I tried it as the library, helper even separate controller but no luck