This photo shows what the spring assembly *should* look like.  $20.95 at etrailer, but at that price they must made offshore.  I would go US made ones but it looks like Dexter springs are around 4 times the price according to their website.
I would suspect that the spring bushings are totally worn out and it's possible that the holes in the spring hangers are ovalized and need some work.  Again, if planning a lot more miles, I'd go with wet bolts.
Definitely replace the U-bolts as they should not be re-used.
Re & re is pretty straightforward and make sure the frame is properly and safely supported when you've jacked it off the ground.
