fsh4fun05

I have a 2004 3500 Duramax quad cab longbed srw, the carrier bearing is about shot. I'm not sure if it makes a difference but it was put on by the factory backwards (engraved in the metal says FRT with an arrow pointing to the rear). Anyhow, it needs to be replaced. I'm having trouble finding one on the internet and I refuse to pay dealer prices, $145+. I need to find the bearing and have a few questions answered from the pro's.
1: Does the bearing need to be pressed?
2:Where can I find the carrier bearing on the net for a lesser cost?
3:Will you fix it for me?
4:Ok, I'll fix it myself but I could use some help on how.