we used TV as an electronic babysitter...at transition times..
my daughter gets a bitof TV first thing in the morning.. she wakes up a bit crabby and laying in bed for 15-20 minutes watching a show seems to help her.
she sometimes gets a bit of TV when I put the baby down for his nap...
she usuallyget a bit of TV just before bed..
On good days it is less than 1 hour total..
But on a rainy day, and I have headache- it coudl be 3 hours..
Most days are good days.. we try to go out someplace every morning... so we are out and about in the morning.. then lunch and nap then daddy comes home and dinner time and then play outside in the backyard or the park time..
the days just fly by..
You are not a horrible mom for letting her watch tv.. but try to come up with a loose daytime schedule of activities so you fill up the day without too much tv time.