Where should I put the dog with the cage?, because she has lots of flees. (PLEASE READ Beschreibung FIRST)

Do Du just leave her in a cage all day? Because that could be why she's so hyper. Hunde -- even small ones -- need room and daily exorcise. Try letting her actually run. If she's too much in the house (I would suggest obedience training), put her on a leash and take her for a walk until she's tired and calm.

If your fleas are that bad in your yard, Du should probably look into treating your yard, and I'd do a good clean and treatment in your house too. It's possible that she picked up fleas and Du never really got rid of them (you killed the adults, but not the eggs), and they're just coming back in cycles.