Macbook Pro Keyboard Issue. HELP!!!

Okay, so my issue started two years ago;
I accidentally spilled a little water (and not much at all! And note this is not a typical "I spilled liquid on my laptop") on my keyboard... my keyboard stopped working completely though!

I left the computer off for a few days but it still refused to work so I went to the apple store. They sent it off to get it fixed but then said it would cost $1200 dollars to fix it.... So I was like;heck no! I got it back from them and the computer worked just fine except for;

-the caps key
-the left shift
-the right arrow

not hard to get around at all. now two, almost three years later the n key stops working so i turned off my computer and let it chill for a bit for a day.

I come back to it and it's still not working so i turn my computer off and clean it all out... now the little squishy gummy part under the keycap... that button thing (is there a term for it?) came off so the key is totally ****ed... except that if i push lightly into the exposed part the n key works just fine (i'm not using it right now i'm pasting the letter n cause i feel like it'd be bad for the computer)...

Here are my questions;
-could i reattach the gummy button thing myself
-can my other keys be fixed?
-who should i contact?

What don't you replace the entire keyboard? Have your model number handy and go here.

Regards.