Scratched but not broken screen on PRS-505?

[Shoeburyness]

Somehow my screen got scratched-- there are several lines on the screen that can be felt with the fingers, and can be seen with the reader on or off... but otherwise it functions normally. It just annoying, really, everything can still be read. I think what has happened is that the plastic covering is damaged, but the glass and substrate are still OK. Is there anything I can do about this myself? How much does Sony charge to repair it?

It isn't really worth too much expense, because I can read books with Mobipocket on my Blackberry. (I find myself doing that a lot more lately, especially at bedtime, because the BB backlight doesn't disturb my husband, but the amount of light I need to see my Reader does.)