Charging a Battery using Piezos

Hello, I am new in electronics so go easy on me. I have a project, using piezoelectric sensor to a 12 volts 1.2 amp, but the piezo sensor is generating very small current around 'micro' to 'milli' amp. is there a way to amlify the current to 0.5 to 1 amp to charge the battery?

To put it simply, to amplify a signal without using a power source is not possible, furthermore, amplifiers are not 100% efficient, so there are power losses to contend with as well.
If you are using a transducer to generate power, you need sufficient transducer numbers to create the power needed in the final application.
Cheers,
Richard

If I am to get this straight it is possible to amplify the current but with losses. The losses mean instead of getting the actual value of 0.5 amp that i want, I may get something like 0.3 amp. Also, sir i do not know how to go about this since there are various transistors to be considered, maybe if i could get a circuit diagram would be helpful.

It is possible to increase the current, but only by decreasing the voltage. The power output will remain unchanged (actually slightly lowered by any inefficiency in the conversion).

Power out = power in * efficiency

Power = voltage * current

So if you are getting 100mA @ 12V output from your piezo and you need 0.5 amps you would end up with 500mA @ 2.4V assuming the conversion was 100% efficient.

The only way to generate 500mA @ 12V would be to store the power up for a period of time, then intermittently generate an output. Given the 100mA @ 12V input assumption from above, you could store up the input power for 5 seconds, then generate your output of 500mA @ 12V for 1 second. There would be no output for the other 4 seconds of each 5 second cycle.