The term 'God', discussing Norse mythology, is often wrongly mistaken to include non-'God' deities (such as Hel), when really the term 'God' in Norse Mythology refers to any deity who is of the Vanir or the Aesir.
Since the series doesn't come out until 2015, we don't really go into specifics with deities that we don't know will actually be in the series or not. If you wish to change it, go ahead.
As Birdqueen said, change it if you wish. Although again the series doesn't come out until 2015 we cannot assume what Rick will write. As he said in his FAQ, mythology has many different versions, such as a version of Theseus and the minotaur (I heard 2 versions, one being Poseidon as Theseus' father and one that has Poseidon as his godfather). So we cannot conclude that Hel will not appear as a goddess in the Norse series or if she even appears at all.