Current Acquire on PC

Hello every one,
i hope you are good there, i am right now working on acquiring the voltage and current from transformer to the computer through data acquisition card. i have successfully acquired voltage through Analog to digital converter and then with the help of micro controller 89c51 to the computer through serial port.
Now i have total 20A in the load which i want to acquire kindly help me what should i do i have 20//5 A current transformer right now.

I think you are going to spend more time and money inventing something you can buy off the shelf and then you have to consider the calibration (i.e. is it accurate to a known standards so you can trust your measurements) dont forget safety - you did not mention the common mode voltage it may be off the power line. consider just buying something known to work that comes with free GUI software
http://www.newtons4th.com/products/power-analyzers

I dont have an agenda here but - I would not build something you can buy ready to go out of the box with traceable calibration.

Kevin Parmenter