When you are short on time do circuits of both.
If you do sculpting in super-sets/pairs with short bursts of intense cardio, you can bust through a fantastic fat-blasting AND muscle sculpting workout in 25-30 minutes. Here is an example of a circuit you can use (do NOT rest in between exercises - move from one to another):
-15 body weight or weighted squats
-15 push-ups or a chest exercise (chest press, bench press, etc.)
-1 minute jump rope or high intensity cardio
(repeat this sequence 3 times and move to the next)
-15 lunges
-15 rows (bent over, single arm, cable rows, or band)
-1 minute burpees or high intensity cardio
(repeat this sequence 3 times and move to the next)
-15 bicep curls
-15 tricep extensions
-10 shoulder press
-1 minute run (in place or on treadmill or track) or high intensity cardio
(repeat this sequence 3 times and move to the next)
-20 crunches
-20 twisting crunches
-30 second planks
-1 minute jump rope or high intensity cardio
(repeat this sequence 3 times and move to the next)
This circuit hits nearly every muscle group and keeps you moving from one exercise to the next. Your heart rate will be up there! Contrary to popular belief, strength training if done correctly can be an excellent cardiovascular activity. On top of that, as you build more muscle tissue your metabolic needs increase because muscles require more fuel while at rest and you'll be turning your body into a calorie-burning furnace. The good news is that as a female you do not possess the amount of testosterone that is needed to build huge man-muscles, so no worries there!
If you have to decide between the two, take a look at what you've done for the week and decide which area could use the attention.