Onder, I think if you want to do a 5 day split I would recommend a 4 day split, you could split it up this way :
d1 - lower body - squats, lunges -- you can do a variety of lunges, front, back, side, walking... I'm not sure if you're at a gym but if you are you can do leg presses, leg extensions, leg curls, all these are on a machine, but there are alternatives, you can look them up on line...
d2 - chest and triceps
d3 - back and biceps
d4 - shoulders, abs and core
Do 2-3 sets of 8-12 reps, if you can do more than 12 reps it's time to go heavier, if you can't do 6 reps go lighter on the weight...
If you are working out at home you can use a ball, some resistance band both fairly cheap... 5, 8, 10 lbs dumbells are cheap too ...
Then start day one again... by this time you've had 3 days rest from doing day 1. You'll see results even if you only work one body part per week, but the intensity must be there... Don't be afraid to go heavy on weight training, women can NOT bulk, if it were so easy to bulk up wouldn't it be easier to tone, and we all know that toning isn't that easy... So don't be shy with going heavier when it comes to weight training.
In the Weight and Resistance Training section there is a
Resistance Band Workout
which you may find interesting...
As for the cardio part of your workout eventually you'll need to step up the intensity, I don't know how you could do that with Wii Fit though, as I have no idea how that works ...
Hope this heps, ask more questions if you're more confused now than ever