How do I get to the new area(s) in the Prepare to Die edition?

I originally played through Dark Souls on the PS3 and now am playing the Prepare to Die edition on the PC. I've gotten to the point where all I have left to do is kill Lord Gwyn, but I haven't stumbled upon any of the new areas.

What are the new areas, and how do I get to them?

Solution 1:

In the are you kill the Hydra in Darkroot Basin, where the golden golem was, you will find a portal to the new area.

To reach this area you will need to kill a new, special Crystal Golem that appears in the first populated room of The Duke's Archives, it will drop a Broken Pendant.

With that pendant, and after killing the gollem and saving Dusk of Oolacile (the lady that sells magic) a portal will appear in the place the lady was.

Check the walkthrough of this page:

http://darksouls.wikidot.com/sanctuary-garden