micro water pump set up
Using a 4.5V pump with a 12V power supply has probably burned out the pump. The voltage of the power supply needs to match the voltage of the pump.

I suggest you find a 12V pump to match your power supply. Or: a get a new 4.5V pump and find a 4.5V power supply to match your pump. (Or 3V. The 3V/4.5V pump will run slower on 3V than on 4.5V)

I don't think you need any extra components.