What you need to change is the phone app. Not the dialer, but the phone app (it's not the same thing). The phone app cannot be changed unless the device is rooted.
If the device is rooted, you have two options:
1. Install a custom phone app
2. Modify the existing app
Option 1 is extremely risky. The phone app must be very precisely tailored to your particular device, because it works at a very low level. It works directly with the radio hardware of your phone. It must be a perfect match for your hardware. Even a phone app from another S3 may not be 100% compatible with your phone, unless it's the same model number.
Option 2 means extracting the app from the phone, unpacking it, modifying it to suit your needs, then signing, packing and uploading it back. I guess it's not impossible, but you need to know exactly what you're doing. It's not an amateur job.