Re: Level 76 + having lots of trouble act 1 hell.
You should start running Nightmare countess for some runes, and, if you can, run Nightmare Mephisto. Right now, the only thing really worth keeping is the weapon, but even that could use some major improvement.
Here's some priorities for your gear:
1. Life. At minimum, you should have at least 1200 life as a melee guy.
2. Cannot Be Frozen. Frozen = slow. Slow = dead.
3. Life steal
4. Resists, especially fire and lightning. Cold and poison don't usually do as much damage, and can be supplemented with antidote and thawing potions (they give a 30 second resist boost. Drinking more increases the duration).
5. Blocking. Since you have Holy Shield and 140 dex, this shouldn't be an issue.
6. Crushing Blow, especially if your damage is on the low side (which it is).
7. Damage reduction. Percentile or 20+ integer.
8. Mana steal
9. Faster Hit Recovery
Here are a few cheap/easily found suggestions. There are much better things out there, but these should (hopefully) get you by. I probably forgot some things in this post, but at least you know what kinds of things you're looking for.
Gloves:
"Blood" crafted: life steal, life, crushing blow
Rares.
Helm:
Rockstopper, sallet: resists, damage reduction.
Vampire Gaze, grim helm: probably harder to get. Has damage reduction and dual leech.
Guillaume's Face, winged helm: Crushing blow, deadly strike.
Tal Rasha's Horadric Crest, death mask: life, resists, dual leech.
Body armor:
"Smoke" runeword: big resists, some defense
"Lionheart" runeword: stats, damage, life, resists
Duriel's Shell, Cuirass: cannot be frozen, resists, life, defense
Shield:
"Rhyme" runeword: some resists, cannot be frozen
Moser's Blessed Circle, round shield: resists, blocking, two sockets
Gerke's Sanctuary: Resists, blocking, damage reduction.
Boots:
Goblin Toe, light plated boots: Crushing blow
Tearhaunch, greaves: Resists, faster run/walk
Rares.
Belt:
String of Ears, demonhide sash: life steal, damage reduction
"Blood" crafted: life, life steal, open wounds
Rares.
Rings and amulet:
Rares with whatever you're lacking. Blood crafts could be good here too.
You can read more about the items, runewords, and crafting recipes here:
http://www.battle.net/diablo2exp/items/