the quest giver for the hearts should have given you a container to combine them in.. the container for the final quest is bought from the godly point vendor.
Iirc you can just delete the quest and get it again, thus giving you the box again and you just need to combine the hearts for the Stone without necessarily completing the quest.
I believe you must repeat the group quest in its entirety. Kill checks and loot checks keep you from taking any short cuts, even the second time around. Doing the combine with the hearts you have without completing the quest will result in the raid quest NPC not speaking with you until it is complete. At least I think that's how it how it works.
Ah yeah ofc, hearts is Group quest isn't it - ignore me then. Though, unless you can get reimbursed (Highly unlikely) it's probably your only choice to re get the quest. If you're about then shoot me a tell, we can run through the mini's for ya.