Change and upload source code for wifi router device

Looking for a linux, hardware/software specialist to change source code for wifi device, Operating System is Linux. And then upload this source code to the device, and show me how. I only want one specific change, that is to block all other website addresses and allow devices that connect to the wifi device, not to connect to any other web addresses, except only one. The device is vodafone R207-z . My budget is $60.