I got all of the dlc but it seems like i have to start a new game considering my saved game would automaticly start confroonting the enclave at the purifier. Is there any way to play the dlc without starting a new game?

Load your save with Broken Steel downloaded, kill or convince the Enclave to leave, then wait and see if the DLC pops up before you enter the purifier, if Broken Steel pops up before you have to enter the code; then Yahtzee, game with DLC.