Dark Souls Sorceror Help

Hey guys I have been following the ign guide trying to work my way through Dark Souls. I am a Sorceror level 39 with the following stats:

Vitality: 26

Attunement: 15

Endurance: 14

Strength: 9

Dexterity: 11

Resistance: 8

Intelligence: 27

Faith: 8

The only armor I have upgraded is my helm (Fang Board Helm) and my Cloak is +2 (the other shards went to upgrading my dagger).

Now I have been following IGN's guide and I am the part where I am in the Darkroot Basin attempting to kill the Hulking Knight right before I pull the Hydra boss fight. IGN states "Keep your distance to avoid his hammer and you should be able to kill him fairly quickly." First, if I do get hit by the hammer as I'm rolling then it almost always kills me (sometimes I'm left with a smidget of HP). Secondly, even if my Soul Arrows hit him cleanly for maximum damage (he likes to roll and dodge them or block them with his shield) they do a whopping 46 damage. Meaning I don't even think all 30 of my arrows would kill him.

Edit: This guys name is Havel the Rock apparently.

Have I just not been killing enough mobs, i.e. am I not as high in level as I should be at this point in the game?

As an aside, IGN keeps mentioning using the Heavy Soul Arrows in hard fights if you have them, but never mentioned where to obtain them. Should I have the Heavy Soul Arrows at this point in the game?

Edited on Sep 8, 2012 7:35 pm GMT

Go the the trader guy in the Undead Burg and purchase the Residence Key. Then, go into the area where the ninja guys are before the Capra Demon and use the Residence Key to open one of the locked doors. There is a sorcerer apprentice in there that will relocate back to Firelink Shrine once you rescue him. He will sell you stronger magic.

As for Havel, he has really higher Magic Defense, so my advice is to stab him in the back with melee weapons. His attacks are very slow and take him a second to recover so make sure you equip load is at 25% so that you can roll as fast as possible. When he attacks, just roll to the sides and then go around him for a back stab. Repeat this and you should be able to kill him rather easily.