Is it a breech of my apartment lease agreement if my Landlord refuses to fix my air conditioner, in nevada?

I've already notified her about our ceiling leaking, near the A/C. On the 31st it will have been 14 days since my written notification. Today I had a plumber crawl into my ceiling and check out the problem, and he said it is not the plumbing, its the A/C. Regardless, I have now left at least 10 messages on my Landlords message line, and she hasn't responded since 8/04 (when she left me a message advising me to have it fixed with her approval of the estimate obtained by a plumber) ...with no reponse to my messages, thats when I decided to notify her in writing of my repair request. Now that we know it is the A/C, I'm wondering if the time limit to fix this repair is shorter, and if she won't take action-or acknowledge the problem, is that a legal reason for my to end our lease agreement, since she is in breach?