Another Rear Brake Problem

[SlappieBooBoo]

SO i was changing my break pads when i came across a few interesting things.
1. My passenger side rotor was ALL chewed up and the pad that touches my piston was down to the bare metal. This makes me think that maybe that caliper is fucked.

2. The piston on the passenger side was REALLY hard to turn in but i got it.

Now i finished putting the pads on and my breaks are hella loose. The stopp
ing power feels less than before and my ebrake pulls up hella far...wtf

so is it that my caliper is fucked or do i just need to bleed my brakes? let me know thanks