2007 Kia Rio, air conditioner is barely blowing air, radio went out long ago

I don't know if this is the problem, but I had this same problem description on my `06 about 2 years ago. We bought a can of coolant, put it in and had a worse problem. Took it by a local garage and put it on their machine. It showed waaaay to much coolant, so those canned coolants gauges are not correct. They took out the overfill, and opened up the glovebox, swung it down and took out a cabin air filter I didn't even know the car had. After replacing the filter the air conditioned air could now flow. I even found a piece of a plastic bag in the hole. That may be a way to start.