Checck your inventory, do you have Leandras spell?
Check carefully...
If the answer to tis is 'no' and you dont remember where you put it then you are screwed in deed.
If the answer is 'yes' then what you need now is the second component to the anti-DK spell.
Did you do the Immaculate trials?
Go to Silverglen and talk to Loic (I bellive) in the chapel. He will get you started.
Alternatively, if you have high enough lockpicking, accessing the hatch in the chapel should do the trick too.
Either way, this will grant you access to the SE area of the map.
What is the item called (Leandra's spell that is)?
I finished the trials and went down the hatch in the chapel and did all that. I've found Sacred Stone and walked around in there for a bit.
What is the second component? Some blood if I recall correctly?