Nikon no longer sells parts to independent repair shops in US. How badly did you tear it and what is the extent of the damage? While exact parts may be hard to impossible to obtain, if all you broke is the flexible circuit board, which I mean the tape like flexible structure with straight trace on it, you may be able to find something similar as these are fairly common. It does require some understanding of electrical circuit and manual dexterity to repair it, it's not impossible. It's really hard to be any more exact without seeing what you've done.

Where in the world are you though? US?