Since no-one has responded to you yet, I shall put a few thoughts down.
I would break this up according to a cardio *2 per week and weights *3 per week, if looking at 5 workouts per week. But! I don't think you can focus on improving strength on this regimen, as you suggest, probably only maintaining what you already have, until such time as you can do longer weight sessions or splits or whatever.
Also! I would agree that the 3 weights workouts should be total body, but I would try and do them as circuits, or supercircuits using compound moves so that as many moves as possible use the upper and lower body together and with exercises back to back with very little rest so that you both maximize your time and create a "cardio" effect.
Then, as you suggest, you could try and make at least one of your cardio sessions an interval-plyo based one, as these can really ramp up your fitness.
If you haven't already, check out Kelly Coffey-Meyer's website at coffeyfit.com. Her latest series of workouts are entitled "30 mins to fitness" and each DVD features 2 30 min workouts. She has 6 titles in this series so far and they span the range of tough kickboxing, tough bootcamp, weights, step cardio and plyo moves. Each DVD also has abundant premixes so that when your time is yet again freed up for longer workouts, you can indulge. You can read reviews of these DVDs on collage also. They are well liked. Kelly can work you hard in 30 mins, particularly, I think, her bootcamp DVD, which is circuit training after all.
Does this help?
Clare