You haven't read enough...
j/k
Umm...IMO the routine is not that good. I would reduce the reps to 5 or 6 for some exercises...
If I just changed some of the stuff I would have you do:
Monday:
Squats – 5x5
Overhead Press – 5x5
Dips – 3x12
Situps – 3x20
Tuesday:
Cardio – 45 mins jogging on treadmill
Wednesday:
Lunges – 3x8
Bicep Curls – 3x12
Pulldowns – 3x12
Swiss Ball crunches – 3x20
Thursday:
Cardio – 45 mins on bike
Friday:
Deadlifts - 5x3 or 3x3
Stepups – 2x12
DB Bench Press – 3x12
BB Bent Rows – 3x12
Hyperextensions - 2x20
--x--
This is just basic....but once you learn that compound exercises are better than isolation exercises you can mix things up....But this looks better than before. Though, if it were really up to me I would remove all arm work and add in more lower body work and more upper body work.
Push-ups
Pull-ups
Glute Ham Raises
Front Squats
are just a few...