Hello,
my name is Josef, i'm professional developer from Czech Republic, and i would like to offer you my services.
I understand your project description, and i can convert your current Magento 1.x payment module to Magento 2.x module. I have done this before, so i know exactly how to do it, and what's need to be done. However it's time consuming process, henceforth the price.
If you have any question or more information, please contact me by chat. Also please let me know, if the payment gateway supports testing mode. I hope you will choose me for this project, and i'm looking forward to our cooperation.
Kind regards,
Josef