Off the top of my head, your Automatic sounds like it is in limp mode and needs a new valve body, which might be cheaper than converting it to manual. Off the top of my head, to do the conversion, you would need ...
0) ... not certain on this one, but an ECU from a donor car that has a Manual transmission
1) ... a Manual
Transmission
2) ...
Clutch Kit with Fly Wheel
3) ... Mounting Studs and Hole thru the Firewall for parts 4, 5, 6 and 7
4) ... a
Clutch Slave Cylinder and a
Clutch Master Cylinder Assembly with Clutch Pedal
5) ... a Brake Fluid Reservoir with Master Cylinder Tube Connection
6) ... a Wiring Harness to connect the Clutch Pedal Switch to
7) ... the Shifter with ALL Associated Cables, Linkage and Mounting Brackets
8) ... and ALL of the Nuts, Bolts and Washers to mount everything