The refrigerator section is a little warmer than normal, even on the highest cooling setting. (But I figure this is due to the freezer not being cold enough). The freezer section is about the same as the refrigerator - about 50°. Any ideas what I can do to repair?

I have just noticed that the section in the front and in between the freezer and refrigerator stays extremely hot. Could this be caused by the defrost timer not working?

No, it's supposed to be hot. Check your defrost heater first. It's at the bottom of the freezer coils. You can test it with an ohm meter, but if you look at it you can tell it it's bad. It will be obviously broken.