I assume you are not currently rooted, so this will work for you.
Your phone is not automatically detecting the update, so you will need to manually update it (no rooting required!
)
Download this file.
update.zip - 4shared.com - online file sharing and storage - download
Place it on your SD card (make sure it isn't in any folders, though! Very important!)
Now that this file is on your SD card and your SD card is in your phone, take the battery out of your phone and put it back in so your phone is completely off.
Now hold down the volume down, power, and camera buttons. You will go to the stock updating tool.
Select "apply update.zip"
Boom! Your phone is now updating
PS,
In the stock recovery, I believe you use volume up and volume down to navigate the menu, and either the menu soft key, the camera button, or the voice command button to select. Just test which one works, it won't harm your phone!
Glad to help,
-Cooper