the 02-06 ES has a bumper cover. It is less than $250 online.
see here
The cover can be removed and repainted. If it is gouged as you say, it may be easier to just replace with new and have a body shop repaint. Your insurance should cover it and make sure they wave your deductible because it wasn't your fault.
here is a picture of the rear bumper parts for the 02-06 ES.
here is the key:
Please select a corresponding number from the illustration below to view the details of that part.
1) Bumper cover 2) Clip Upper 3) Side support Right
4) Side support Left 5) Fastener Fastener Back 6) Bolt #1
7) Bolt #2 Back 8) Washer #1 9) Washer #2
10) Nut Nut Back 11) Side support Screw 12) Protector Protector Back
13) Energy absorber Lower 14) Energy absorber Upper 15) Bar
16) Seal 17) Reinforcement 18) Reinforcement Nut
I hope this helps.
steviej