PIC's output is 5V at most, and you need 12V to switch the relay coil. So you will need a transistor, you'll hook one side of the coil to 12V and the other to a transistor which will ground the other side when on. So you'll need an N-channel MOSFET or an npn bipolar with an emitter resistor.
The UCC27322P is a driver for a MOSFET gate, but the PIC pin can drive a gate on its own with no problems unless you've got a "special needs" application. I don't know what a BC547C is.
Regardless of which transistor you use, you must put a diode across the coil because it kicks out a high voltage surge when turned off.
You might also be able to switch the load directly with a transistor (no relay), depending on what you need to do.