You sir need to fix that res issue, or certainly you're toast.
Lets just pretend that you're pretty darn strapped for items and whatnot. Here are some of the ways you could pump that res up:
Shield: Ancients Pledge = ~45 to all
Helm: 3 socket with ort, ral, thul = 35 lightning, 35 fire, 30 cold
Armor: 3 socket with ort, ral, thul = 35 lightning, 35 fire, 30 cold
Right with those 3 insanely easy to make items we have about +75 to all but poison. You didnt post your gear so I'm not sure what you're capable of assembling. However, considering what is now available just with trading perfect gems, I'm going to say that the following setup isnt out of anyones reach. So here is a better overall setup with good resistance.
Shield: Steelclash = 15 to all + 19 with a perfect diamond (34 total)
Armor: Smoke (Nef+Lum) for 50 to all... not hard to get a Lum
Helm: Rockstopper avg. 30 for each except poison
Amulet: Gambled magic prismatic +15 all
Ring 1: Magic +20 fire
Ring 2: Magic +20 lightning
Gloves: Rare with +15 fire, +15 cold
Boots: Rare with +15 lightning, +15 fire
Belt: Rare with +16 poison, +10 cold
With this we get:
Fire: 179
Cold: 154
Lightning: 164
Poison: 115
However, notice these numbers... with a few charms in your inventory you can easily get to 75 for all in hell. Your items are likely to be better than what I listed here for several slots, as well. Check my guide on the front page for plenty of other gear recommendations but this should help focus you a bit. Rares can help a lot as far as res goes and CHARMS CHARMS CHARMS! =)
Good luck!