well gee -
It has been a while, but seems to me that when I gave up the Mavin Sword I got Kerah's sword - I think it just showed up (equipped) in the same slot that the Mavin Sword occupied.
When you reset the adventures, you will still have Kerah's Sword (if you have it) and you can give that to any (old or new) character that can equip it.
The amulet is difficult to get, very difficult. I remember that I was very disappointed when I finally did get it considering how much effort it took to get it. I figured it was going to be the very best amulet ever. I think I ended up jumping up on the stones near by in order to get close enough to finally jump and grab the thing. I can't even tell you at this point what the amulet is but I decided after getting it that it wasn't worth the effort. Pity.
Wyv