Rear wheel bearing (disc brakes)

My wifes PT was making a weird noise (not typical brake squeal), so I pulled the rear wheels and found that the driver side brake pads were completely gone, while the passenger side was still in very good shape. I want to replace the rotor on that side. Are the bearings reusable, or do I need to get new ones and have them pressed into the new rotor? Any way to get them out of the old rotors without a press?

Also, any ideas on what may be causing the uneven brake wear?

Thanks!!!

The rotors just slide on. You only need to remove the caliper, caliper bracket, and the locking washer located on one of the lug bolts to remove the rotor. Need a needlenose pliers to unscrew the washer. Release the parking brake too or you won't be able to remove the rear rotor. I would check the calipers but the OEM brake pads aren't the best or longest lasting (applies to all makes and models). Can buy metallic or kevlar pads for the rear and ceramic or kevlar pads for the front. They don't make a ceramic pad for the rear if you were wondering. Ceramic pads are a no/low dust design and brake performance and longevity is good.