elliptical for 30 min or strength training?

So....since I started working out at the gym I have been doing mostly cardio. (elliptical, stationary bike, treadmill)
Me and my daughter done Zumba once, haven't been able to make it back to do it againg due to my work schedule.
If all plays out well then I will go back and do it again because I loved it. Oh, and last night we done kickboxing, it rocks!
On to my question....
one day I challenged myself to see if I could actually finish a full summary workout on the elliptical, and I did, a full 60 min and then 5 minutes of cool down. Ever since I seen I could do it I feel I should, however I am wondering if I am spending too much time doing cardio!
I don;t want to stop doing cardio because I know its good for me. How much time would I need to spend on it for it to be beneficial but not be too much?
Next....would it be better if I done, let's say 30 min on the elliptical at a higher resistance and ramp to push myself some and then do my strenght trainging?
Please some opinions would be greatly appreciated!