I want to lose weight, how much cardio to do?

'Ello I am 50 pounds overweight, I have been doing 30 minutes of cardio (running) every day. Right now my pace is about 5:30 minutes per kilometer and I run for 30 minutes. My goal is to get a time of under 25 minutes for 5K. Is this enough cardio each day to lose weight as well as me dieting a lot?