1998 Dodge Caravan A/C problem

A few months back the A/C was repaired in my '98 Grand Caravan. The compressor and condensor were replaced along with the schrader valves for the high and low side.
The A/C was working fine until two days ago. The blower motor was taking a minute or two to reach normal operating speed. The air was cold coming out of the front vents, but the air coming out of the rear vents was blowing warm. Then, today no air was coming out at all from the front vents, but the rear vents were still blowing warm air. There are 2 seperate switches to control the air flow for the front and rear vents.
I understand that the blower motor may be going out, but what else might cause the problems we are experiencing? Thank you for any help you can give me.