Can I quickly replace a cracked glass trackpad?

I recently dropped a tiny bit of water on my trackpad and the mouse started acting up.. moving on it's own..clicking everywhere. I wiped the water right away and opened the back case to let it dry. I used a blow dryer for a few seconds near the trackpad then put a regular fan next to the computer. Sadly after 4 days it's still not back to normal and I managed to crack the trackpad a tiny bit at the bottom as well so now I really want to replace it.

Someone linked me to this site but I can't find any tutorials on how to replace ONLY the trackpad. Is there an easier way to do it than having to unscrew the whole upper case?

I've never done anything like this in my life but I'm afraid I cannot afford to have it repaired at a shop (according to apple an upper case replacement is around 340$CND?) This is a Late 2009 machine.

Any advice for me?

Thank you very much

Claudia M.