2001 Chevy Blazer 6 cyl Four Wheel Drive Automatic 170000 miles

My Blazer has lost the spring and roller assembly on the top hinge (attached to the vehicle) of my drivers side door. The upper hinge (the one attached to the door)has cracked near the pin and the door is now sagging about 1/2 inch and will not close properly. The hinges looked welded on, not bolted. Do I need to replace the whole door to fix this? Can the hinges be replaced? Any solutions?

Hi:
Part of the hinge is welded, but the pins are replaceable. They come with shims to take-up space created from use.

Joe