As far as the heims go, they just wear out occasionally, it is something you have to live with if you are running them. I replaced the heims on my track bar yesterday. There may be better ones out there, but ive been using ruff stuff heims on my jeep. Link here.
The size will generally refer to the diameter of the threads. If you have any measuring calipers, thats the easy way, but you can probably measure them with a tape measure. Check the Thread diameter and when you take it off measure the size of the hole where the bolt goes. Call Ruff Stuff and he could be able to fix you up.
You need to figure out what size lift you have, if any lift. You dont have to replace with the exact shocks, you can buy alot of different brands based on your lift size.