help in sampling with an a/d converter

[konstantis]

Hi!I have a project to do concerning a sampling of a waveform by a a/d converter and 
 the reconstruction of it with a d/a converter.The converters are about to be bought ready.The point is how to make them work and cooperate on the same "circuit".The number of bits of the converters was left to us.We have to take care to keep the cost as low as possible.If someone could make a suggestion it would help me a lot!Even more helpful would be a small general plan of the circuit.Thanks