Hello,
basically Booking supports payment modules similarly to e.g. VirtueMart.
So you can add additional payment gateways as needed.
The current credit card method that is included only supports payments - that is that the operator has credit card terminal where he can charge the CCs based on the received CC number and security code (CVV).
Basically you just need to add the payment gateway file in the appropriate directory, that will handle the communication with the bank of your choose and set the status of order in booking.
The easiest way is to check e.g. how the PayPal method that is included with the standard installation package is working. Most others are similar.
We also offer on-request development of the additional payment methods. So if you send us the documentation for the the bank / payment institution API, we can send you a quote for the development.