The fan remote control receiver used in the Hunter 25730 model fan (see picture) is not available from Hunter. Remove the fan from the ceiling. Remove the receiver and take it to recycling. It can be replaced using a readily available and inexpensive replacement universal remote and receiver controller. There are limitations though. The Hunter receiver provided fan reversing functions. The universal controllers do not. You therefore have two options.
Option 1: The universal receiver can be installed such that the fan direction is fixed, either up or down, all other functions operate normally.
Option 2: A reversing switch can be purchased from Radio Shack for about $4 and installed in the fan. This does require cutting a square hole and drilling two bolt or rivet holes in the side of the cylindrical housing which previously housed the Hunter receiver. I'd suggest the Radio Shack DPDT slide switch part number 275-403.
Refer to the wiring diagrams and connector pinout diagram for connections. Please note that the connector pinout diagram is the connector that is soldered to the circuit board as shown in the photo of the Hunter receiver. If your motor wire colors are different then with the connector unplugged from the receiver use a multimeter to probe all the motor wires in order to identify two pairs of wires that indicate approximately 70 ohms each pair. These will be the motor windings.