You are talking to other Apple users here, not Apple. No one here can send you an update for your iPod.
If your iPod is a 2nd generation Touch, then it cannot update beyond iOS 4.2.1.
To check which model you have, see http://support.apple.com/kb/HT1353. Pay particular attention to this if you have an 8GB Touch, because if so, it is not a 3rd gen Touch, it's 2nd.
If your iPod has Model No. A1288 etched into the back casing, it is a 2nd generation Touch.