I'd suggest splitting cardio and weights/muscle workouts to different days. You want to give the muscles you work out a free day to repair so you're not damaging them before they have the chance to get stronger. Maybe Monday/Wednesday/Friday could be cardio, with Tuesday/Thursday/Saturday being weights, and Sunday being a rest day?
Keep in mind too that intense exercise makes you retain water, so if you're weighing weekly, I'd have the rest day be the day before your weigh in - a buddy of mine does that, he always gains a bit during intense exercise and sees huge drops after his rest day.
If you're starting up from being completely inactive, for cardio I'd suggest the
Couch to 5k program. If not, well, I can't really suggest anything else to you 'cause that's what I'm doing, lol.