Putting it all together
To find all the extra parts, such as connectors and wires, you should visit your nearest RC hobby shop. You can buy all the parts and crimp everything yourself, but there are also premade wires for this exact setup.
I strongly recommend that you power your Raspberry Pi 2 via the USB connector. The Raspberry Pi Foundation has taken extra care to create a new power filtering system on the Raspberry Pi 2 to help stabilize the Raspberry Pi. Mostly because of all the strange USB power supplies out there, extra filtering and protection is always good.
If you have any extra peripherals, it would be best to connect them directly to the voltage regulator output instead of powering it from the Pi's GPIO or USB port. This will take unnecessary stress away from the Raspberry Pi, and the voltage regulator will easily handle higher loads.