If you want to go for some "cheap" solution, you should try to kill the clone with a Zealot paladin with 95% (or more) crushing blow, and with a Might merc equipped with the unique Thresher (Reaper's toll).
However, I'll write something about this cheap solution for a paladin. A "fast" build.
Stats: strength to wear items, dexterity to have max block (75%) with holy shield activated, energy base, vitality all the remaining points.
Skills: max Zeal, Sacrifice, Fanaticism, Holy shield. 1 in all pre-reqs, all the rest into Defiance.
Gear is the key. I think it's not so difficult to have.
Main weapon: "Black" runeword [Thul + Io + Nef] on a Scourge.
Main shield: "Sanctuary" runeword [Ko + Ko + Mal] on a Sacred targe, or if you think it's too expensive, "Ancient's pledge" [Ral + Ort + Tal] is good. But the huge resist bonus from Sanctuary is very helpful. If you have it, of course, use the Herald of Zakarum, but it can be expensive to get / difficult to find, so I gave you some alternative options.
Helmet: Guillaume's face. Great and cheap.
Gloves: Laying of hands. Same as above: great and cheap.
Belt: Thundergod's vigor. Simply godly. Or string of ears if you like the dr, and leech. But imho TGV is better.
Boots: Gore rider. Cheap and godly for your needs.
Armor: "Duress" runeword [Shael + Um + Thul] on a Dusk shroud or (if you like it more) Archon Plate with nice base defense. If you think it's too expensive, use Duriel's shell.
Ring 1: Any Ravenfrost = godly.
Ring 2 + Amulet = Angelic set's combo. Tons of AR (useful when you have to give the last hits to the clone) and nice stats.
Secondary weapon (switch): The best weapon would be a Stormlash. But since it's expensive, any Demon limb / Nord's tenderizer / Baranar star will be very good.
Secondary shield (switch): another Sanctuary or Ancient's pledge, depending on how rich you are.
Hireling: might merc (Offensive, hired @ nightmare) with The reaper's toll (better if it's shaeled), Duriel shell, and Blackhorn's face.
Note: if you want to put something in the sockets, use Shael everywhere. It's cheap, and gives more fhr, that is always useful.
With this gear, you have maxed your crushing blow (40% black + 15% gore rider + 35% guillaume + 15% duress = 105%, but the cap is 95%, so you're set).
You need some charms, in hell, to max your resists. Keep in mind that you need only high Fire / Lit res when facing the clone. So try to have, with your charms, 75% fire res and 85% lit res. If you have these resists, you're a god vs the clone, he will make very low damage on you (the annoying skill he uses is Armageddon, that is quite damaging, but his other attacks will be quite useless if you have the resists).
Tactics: at the start of the battle, use your primary switch, and attack repeatedly the clone using Smite + Fanaticism. Smite is an ITD + ITB skill, and this is awesome. Let your merc help you, cuz when he hits the clone, he can cast Decrepify, thus increasing your physical damage A LOT.
When the clone's hit points are very low, and your crushing blow's effect is quite useless, switch to your Weapon 2 / Shield 2. And finish the clone using Zeal + Fanaticism.
EnjoY.
(Note: this build is very similar to the frost zealot build suggested in a post of this thread; but I don't like the frost zealot option cuz holy freeze is totally useless against the clone. The Smite / Fanaticism and then Zeal / Fanaticism combo are a lot better. And I also made some corrections / gave some alternatives to have the right - and cheaper in some cases - gear).