I want to be able to do crunches, sit ups, push ups, tread mill, weight lifting for arms and weight lifting for legs.
How can I fit this into the week and have friday and saturday off?
Do them different times of the day.
I exercise when I wake up.
During lunch, I exercise again.
Before I go to bed, I exercise again.
Treadmill is great for when you wake up. Pushes the metabolism up so you are fully awake to face the day.
Do squats at work. Any counter top will do.
Sit ups and push ups and weights before you go to bed.
You will also sleep better.
Instead of trying to do everything at once, have 3 to 4 10 minute sessions a day. You'll be more inclined to stick with your schedule and the workouts will be just as effective. For example, do sit-ups after waking up, do push ups on your lunch break at work, do crunches before bed, go on the treadmill upon arrival from home, etc.
Strength train on Monday and Tuesday, do interval training on Wednesday (1 minute sprints, 2 minutes walking for a total of 20 minutes total), strength train on Thursday and Friday. Rest Saturday and Sunday.