The top three sections of my fridge on my fridge/freezer is'nt working? ?

The top three compartments of my fridge/freezer has stopped working and is very warm to the touch........the bottom three sections are fine.......cool to the touch. The freezer section is also fine. The temparature gauge for the fridge keeps flashing the number 3. How can I go about getting this fixed? Oh, by the way my fridge/freezer was purchase approximately 7 years ago. Should this be happening....never gave any problems what-so-ever before.