Keyboard: replace metal undercasing for 3 keys or entire keyboard?

Hi!

Thank you for taking the time to read my query.

I managed to clean and repair a keyboard on a 13 inch 1181A except for three keys. With these three keys, if you press down nothing happens. However, if you hold the key down and then--while holding it down--move your finger vertically (towards the screen and then towards the mouse pad) repeatedly the letter will appear several times. Then they have to delete the extra times the letter appears.

I removed key and plastic casing and when I placed my finger on plastic covered bump and moved it vertically repeately, I had the same result. So this plastic bump seems to be defective for these three keys.

What do you suggest? Can I fix these three keys? If not, how would i fix the mechanical workings underneath the white housing and plastic casing? Is this something I can do by watching a video or do I need to have the owner go to the genius bar ...this might be expensive for an older computer.

Specs--

Apple MacBook "Core 2 Duo" 2.0 13" (White-SR) Specs

Identifiers: Late 2007 - MB061LL/

Apple MacBook "Core 2 Duo" 2.0 13-Inch (White - Late 2007/Santa Rosa) features a 2.0 GHz Intel "Core 2 Duo" processor (T7300), with two independent processor "cores" on a single silicon chip, a 4 MB shared "on chip" level 2 cache, an 800 MHz frontside bus,

Thank you for your time,