How do I get my landlord to install new carpet?

when I moved in 2 years ago, the carpet was already bad off and he said he'll look into it in 6months (after making sure the dog is housebroken...which he is). We are now 2 years later and I have discovered that the carpet hasn't actually been changed since 2 tenants ago!! Thats about 5-6 years! I don't want him to raise the rent but I do keep the apartment up nicely and have done some landscaping at my own expense. do I have a chance at new carpet?