[banden]

If you're not comfortable with Linux Bash commands, I can't recommend 'Root Explorer' enough. It's a paid app at the market that does everything through a GUI.

Button that toggles mount read only/read/write
Permissions (chmod)
Moving files from sdcard to the system files.

For your issue, you'd find the file on your SD card and select "move" then navigate to the System/apps folder, turn on read/write, hit paste, turn off read/write and you'd be done.