You can't replace the bearing due to the electrnic sensor being part of the assembly. I bought the Motorcraft hub assembly from RockAuto for much cheaper than the dealership or what Autozone/OReilly had. Search for 'HUB115' and was $120.
Once the brake caliper, mount, and rotor are off, its three bolts and with wiring harness... pretty easy. You might want to go ahead and replace the front pads and turn the rotors at the same time since you have one side already off.