"What I suggested to myself is, using some good digital voltmeter board in the front end, and use its digital readout in the back end of the project by interfacing with the micro.........For example using ICL7106 of Maxim."

Have you suggested to yourself the LT 7135 ? I have and I am a happy man today. ( OK its a dual slope integrating type and I don't know what speed you are looking for.)If speed is not an issue, then this fellow is worth a try.

Raghu