Hi nidawatyzainal,
yes i agree with karesz. We need more information to be able to help you. Is your signal in the milli-volt range, or micro-volts, or nano-volts? Also, what is the signal impedance? What is creating this signal - is it some biological process (in which case it may be swamped with lots of 50Hz common-mode mains power signal, and therefore you will need a differential amplifier).
Also, what is the bandwidth you need? And what is the power supply you wish to operate the amplifer from, and what is the load you wish to drive.
Hope this helps.