The other poster is correct, some babies are not nappers.
Other than placing her in a swing or going for a car ride and leaving her in the seat when you bring it in the house.....How long do you let her cry...maybe she would cry herself to asleep. If you are a stay at home mom she may want you in her sight all the time....I would not let her cry more than 10mins, but have you tried that?
Good Luck.....