That is an unhappy looking boxwood.
Never water on a schedule, watering should be done when the tree needs it. Water it from the top, using either the hose with a sprinkler head on it, or a watering can. Water it until the water runs out of the bottom, and then don't water again until the top part of the soil is dry and the bottom part of the soil is just damp. Use your finger, or a chopstick stuck into the soil, to tell how the underneath soil feels.
Two hours of filtered sunlight through your window definitely wasn't enough. It's hard to tell from photos whether your tree will recover, but the best thing to do is to put it outside (which you have done) into a place where it will receive morning sun and afternoon dappled shade, or something like that. Let the soil dry out some between waterings, especially since those crispy leaves aren't using much water. If the roots stay too wet all of the time, they will rot.
Even though the crispy curled leaves look like they need water, it could be a symptom of too much water also.
Also, check for bugs, but that doesn't look like your problem.
Be patient, a sick tree can take a very long time to recover. And if it doesn't recover, go and get a new one, and learn from your experience. Most of us have lost plenty of trees, it's all part of learning bonsai.
Good luck!
Joanie