if I were you, I'd get rid of the saturday circuit training. I just don't see a reason for it, with you having 3 lifting days and 2 cardio (intense cardio I'm assuming) days. If you feel like you need more cardio done, do a medium-paced walk on an incline after your workouts on M-W-F for 15-20 min. I think it would be a good idea to give yourself 2 rest days.
As for exercises.. hell, there's so many you could do, I dunno how you got bored. 3 weight training days is a perfect split IMO, there's so many different variations that you could come up with.
For example, follow a routine for one month, then throw in different exercises.
Routine 1: Monday: Legs
Squats - 4 sets
Leg press - 4 sets
Lunges - 3 sets
Ham curls - 4 sets
Standing calf raise - 4 sets
Seated calf raise - 4 sets
Wednesday: Chest / Triceps / Abs
Incline barbell - 4 sets
Flat dumbell - 4 sets
Close grip bench - 3 sets
Weighted dips - 3 sets
Hanging leg raises - 3 sets
Situps - 3 sets
Friday: Back / Shoulders / Biceps
Bent over rows - 4 sets
Deadlift - 4 sets
Chin ups - 3 sets
Clean and press - 4 sets
Any kind of bicep curl - 3 sets
Routine 2: Monday: Legs
Front Squats - 4 sets
Hack Squats - 4 sets
Single leg squats (one leg on a bench) - 3 sets
Ham curls - 4 sets
Leg press calf raise - 4 sets
Hack Squat calf raise - 4 sets
Wednesday: Chest / Triceps / Abs
Incline dumbell - 4 sets
Flat barbell - 4 sets
Skull crushers - 3 sets
Weighted dips - 3 sets
Dip bar leg raises - 3 sets
Incline situps - 3 sets
Friday: Back / Shoulders / Biceps
Deadlift - 4 sets
One arm dumbell rows - 4 sets
Pull downs - 3 sets
Push press - 4 sets
Any kind of bicep curl - 3 sets
There.. just some ideas. Something I'd do if I had 3 days for lifting.
As for cardio, if you don't have any knee problems, I'd strongly suggest doing sprints on Thursdays. Just find a football field nearby or something like that, and do interval sprints. Worked great for me until I got tendonitis in one of my knees
