Upgrading?

I have been a customer at Metro for a year or so and lately I have discovered a few things about my current phone That I do not like one being that it is virtually impossible to switch my apps on a sd card. I've had this phone for maybe 7 months. I was wondering if Metro had any type of free upgrade or atleast a discount on upgrading. I've been a loyal customer for over a year and I do not have much money to buy a whole New phone at the moment.