I do not have the piece but my friend did the same thing. Just a hint, next time open the lid first
if you can't find the part I can recommend 1 of 2 things, if you have a soft or hard modded GC then I recommend just clipping the wires from there and running them to a spst switch, then you can toggle open and closed manually. Or you can go Ghetto, and just bridge the connection, then you will only be able to insert games with the console off, or reboot any time you change the CD.
Sorry I can't be of more help, but I was unable to find a part for my friends console when he did this, so we have done both, first the bridge, now the switch.