I've been given a quest to collect an item from Lydia, but she is dead. How do I complete the quest?

Long ago in my Skyrim characters growth, Lydia was my companion, and then I entered a dungeon and it was dark, and I missed with my sword and Lydia died, but I didn't realise for sometime afterward that she wasn't with me, so I had to go back and search, and she was dead in a dark part of a tunnel, so it was a long way back to be able to go to previous save, so I just let it be.

Sometime later when I got married, she turned up at my wedding dead so she's actually dead in laying on the floor just inside the door of the Temple in Riften.

I have been issued a quest from someone in the mages college to go collect an item from her.

Is there a way to complete or cancel the quest? I have the PS3 version, so console solutions will not work.

Similar to this answer, as long as it's not a unique item you might be able to get away with the following:

• Find the item elsewhere
• Go to Lydia's body, "store" the item and then close the inventory
• Retrieve the item from her body.

You can try to “revive” her:

If you're on the PC, you can use the console to "revive her" (or clone her if you please I imagine) by typing

player.placeatme 000a2c8e

(One opens the console with the ~ key, enter the command and press enter/return) Her corpse disappeared for me, and this worked.

(When I tried this, her corpse didn't disappear, but the Lydia that appeared didn't seem to mind.)