Where do I get a new front panel (5th gen. 32 MB)?

The front panel is cracked, but the LCD screen is still functioning. So I'd like to replace the screen before I cut my finger or the iPod stops functioning all together.

Found your installation guide :

第5世代iPod Touchのディスプレイアセンブリの交換

But I can't find the part iself - where and how do I get a new screen to replace the cracked one?

Thanks!