We're gonna need some screenshots of what you are stuck on as most people would recommend you:
- Talk to Sonia in the Inn in the slums.
- Go to the Casino
- Talk to Lady Luck in the upper left hand corner of the Casino
- Get the nun outfits
- Go back to the inn to change into the nun outfits
- Leave the slums
Edit: I'm not sure, but you might have to win a few games in the casino to be able to see Lady Luck. There is a slot machine on the far right you can play, and an Even/Odd table near the top you can play. If you are lacking money (for whatever reason) you can participate in the pie eating contest in the dining area for pie eating champion medallions, sell them, and then play the games in the casino.
Note: I'm only suggesting this option (using the fact that you can get infinite pie medallions by winning the pie eating contest multiple times despite this being a bug) for making money given the limited information of the original post. This is in consideration that they may be actually stuck in the slums (can't use the horse and carriage to leave the area) and are not able to fight battles (using the slimes in the sewers) to gain money that way.