In order to progress above level one ghosts, you need to do lots of very long and expensive research in the shaman tree in the oracle, where you must have already been to open attack of the level 1 ghost.
Advancing your shaman to each of the nest stages is going to help, but it is still very difficult and expensive to get anywhere quickly.
The one potentially good part , is that you can buy Baggi charms, in the clan store, again they are not cheap.
Otherwise you will have to buy bank packages, or win them, when they run a special ghost hunt event.
Here again is another cruel twist,you don't win charms if you are in the rookie league, and you could be in that league a while,even then,they don't give you many charms, even if you do all 10 levels.
You need to have enough charms to open the next level each time you reach the maximum in each level ,and again its slow,because each level costs an increasing number of charms.
You know you have charms to add when you see the arrow pointing upwards. (Hall of Mysteries, or the shaman and the word increase)
The good news is getting Baggi progressing quickly,will help you in other areas of the game.