How much protein should a female consume for weight loss?

I’ve been working out consistently for about a year, but my weight loss has been really slow. I’ve only lost about 15-18lbs. I’ve also changed my diet and started eating a lot healthier. I haven’t been intaking much protein and I believe that is a reason why my weight loss has been slow. How much protein should I take to speed up my weight loss? Are there any recipes, shakes or vitamins I should be taking?
I workout at least 3-4x a week. On average I’m at the gym for 1hr. – 1.5hrs. I’ve been attending the RPM & Body Pump classes at least 2x a week. On the other days I’m doing cardio and weightlifting. I also do resistence training.