You can't get them. You have two choices: either order new arms from Black96SE, assuming he can ship them to you, or get a shop to press in brass bushings. The brass will be a harsher ride, but better handling, and last forever.

-Philip Maynard '95 Contour [71 STS | Track Whore] '97 Miata [71 ES | Boulevard Pimp] 2006 autocross results