Custom Dialer Extension

Gooday.

I am looking for someone to write a custom extension for me.
My Java skills are definitely not where they should be.

The Extension will be around more control on phone calls.
I need the ability to have a custom dialer where I can add 2 buttons (Hold, and Transfer)
These buttons need to send DTMF Digits during an active call.

The Current limitation is that I cant edit the Android Dialer, and that even using the standard telephony tools in MIT, this does not allow me to send digits during an active phonecall.

Do you know who I can approach?

Best Regards

Andre van Niekerk