lost part of Proximity Sensor

Hello,sorry for my english bum I'm italian! I've changed the lcd and the power/sensor cable on my iphone 4, on the back of the proximity sensor there was a plastic block (http://imageshack.us/photo/my-images/69/...), in the front of proximity "originally installed" (http://imageshack.us/photo/my-images/692...) there war a lens (http://imageshack.us/photo/my-images/837... or http://imageshack.us/photo/my-images/708...) I have lost this 2 parts, can you tell me where I can buy? thank you