autrui's guide, altered for Alliance (so all props to autrui):
Here's the entire quest chain, with simple descriptions and quest links for the Horde Alliance versions.
1. The Battered Hilt [you are here]
Bring the Battered Hilt to Caladis Brightspear at Quel'Delar's rest, south of the Argent Tournament Grounds.
2. What The Dragons Know
Speak to Krasus at the top of Wyrmrest Temple.
3. The Sunreaver Plan
Obtain the Orders by killing an NPC in the Dalaran Sewers. Make sure you kill the right one.
4. A Suitable Disguise
Obtain a Borrowed Tabard from Shandy Glossgleam; He is upstairs in the Threads of Fate: if you are standing in front of the stairs with the Violet Citadel to your back, it is to the right (to the left is the toy store).
5. An Meeting With The Magister
Retrieve the Ancient Dragonforged Blades tome from Magister Hathorel. Use the disguise and go in the Horde section of Dalaran.
6. Return To Caladis Brightspear
Bring the Ancient Dragonforged Blades to Caladis Brightspear at Quel'Delar's Rest.
7. Reforging The Sword
Obtain 5 Infused Saronite Bars and the Forgemaster's Hammer and use them to make the Reforged Quel'Delar. (AKA: Run the Pit of Saron. The infused bars are near the entrance; don't forget you have to kill the boss, too.)(It appears this can be done on Normal Difficulty.)
8. Tempering The Blade
Temper the Reforged Quel'Delar in the Crucible of Souls. (AKA: kill the final boss of Forge of Souls; use the quest item nearby.)(It appears this can be done on Normal Difficulty.)
9. The Halls Of Reflection
Bring your Tempered Quel'Delar to Sword's Rest inside the Halls of Reflection. (AKA, obviously, run Halls of Reflection.)(It appears this can be done on Normal Difficulty.)
10. Journey To The Sunwell
Speak with Halduron Brightwing at the entrance to the Sunwell Plateau on the Isle of Quel'Danas.
11. Thalorien Dawnseeker
Visit Thalorien Dawnseeker's Remains and obtain his blessing to wield Quel'Delar. (Go around behind SWP to the Dead Scar (southern end of Isle of QD zone, not in the SWP raid instance) and kill a bunch of mobs.)
12. The Purification of Quel'Delar
Immerse your Tempered Quel'Delar in the Sunwell. Speak to a Warden of the Sunwell when you are ready to enter the Sunwell Plateau. (Possibly different versions of this for sword/mace?)
13. A Victory For The Silver Covenant - (sword or mace)
Bring the Restored Quel'Delar to Veressa Windrunner at the Violet Citadel in Dalaran [sword] / Justicar Mariel Trueheart at the Argent Tournament Grounds [mace].