I can't shift into the highest (easiest) gear without my derailleur going into the spokes.

Here's a pic.



Do I need a new one?
I'm pretty sure it's bent... How much would it cost for a new one?

Also, I can't seem to thread the barrel adjuster back into the RD body. The whole screw came out 'cause I unscrewed it too much, and now it doesn't want to screw back in. Any ideas?