Keyboard key broken off, how do i get a new replacement key?

So, I've broken the J key off my laptop by accident. The little bracket that sits below the key is now missing. So I need to purchase a replacement key. Does anyone know where i can purchase a single keyboard key? If I had to i would probably purchase a complete set of keys so long as i could fix the problem.

I have a Lattitude D630. The keys are solid black, with grey major lettering and blue minor lettering.

Any help would be greatly appreciated.