Hey,
I do believe Apple should provide the parts, but you don't need them!
With your dedication of tearing apart the laptop to clean the keyboard, you can easily fix it. I have actually had this problem myself. Apple keyboards are really bad with water and coffee. Even if you meticulously clean out the keyboard with methylated spirits and hours of work, it still won't fully work. From experience, well a mate of mine's experience.
Luckily your model is NOT an unibody, and therefore the keyboard can be replaced. For the replacement keyboard literally google A2914 keyboard replacement. You can even buy them off aliexpress for 8 bucks if you really want to save money!
Remember to buy screws with the keyboard. It is held down by tiny rivets. When you remove the old keyboard, they all go shooting EVERYWHERE. You then need a hundred or so screws to refasten the keyboard.
Here is a video of the teardown so you can follow along: https://www.youtube.com/watch?v=iEpiyHgYX1Y
Good luck buddy!
Let me know how it goes.