low airflow from heater 2003 grand cherokee

My 2003 grand cherokee has a heater proble, the temp controls are fine and hot air does come out of the vents but at very low speed, my jeep garage has said one of the air flaps has seized and its a 6 hour job to take off the dash to get to it.
Has anyone had this problem and fixed it without a £1100 garage bill?
can anyone help as its bloody cold this time of year.
Steve

The problem is a common one on JGCs with Auto Zone controls, read more here:
http://www.wjjeeps.com/hvac_sub_assembly.htm
You may be able to duct tape the heater doors for a temporary fix.