Macbook top case keyboard repair?

I have an old Macbook (circa April 2006), it's the 13" white. The keyboard is really scummy and I have tried everything to get it clean. There are also a couple keys missing.

I would like to not only replace the keyboard, but the whole top shell. I found some on eBay like this one: http://cgi.ebay.com/APPLE-MACBOOK-13-TOP-CASE-KEYBOARD-TRACKPAD-VERSION-2_W0QQitemZ370125899148QQcmdZViewItemQQptZApple_Laptops?hash=item370125899148&_trksid=p3286.c0.m14&_trkparms=66%3A2|65%3A15|39%3A1|240%3A1318

but I'm not sure if I would be able to install it myself. I'm not very computer savvy but if I could find online instructions I would be able to make my decision. I'm good with my hands but I'm not sure if that qualifies me to replace my top case.

Do you have any instructions or pointers?
How much did it cost, if you don't mind me asking?

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