OK, so what resolution do you need, divide 2Kg by the resolution you need to get the number of bits(you need to make some allowances, so add a bit or two, to allow for not going to full scale on the ADC input, averaging to reduce noise, etc.). At 2Kg you will want near full scale voltage on your ADC to get the full number of bits required. You allow for perhaps 2.5Kg full scale.
At 1mV/V, you need to know your load cell excitation voltage, ideally it should come from the ADC reference voltage so the whole thing is ratiometric. Say the voltage is 5V, then you have 10mV output at 2Kg. If the ADC input is 5V full scale, then you need a gain of 5/.01, or 500. This can be achieved using an instrumentation amplifier, you have to consider that a large offset can be generated since the offset of the bridge is multipled by the gain as well, which without bisaing, can destroy your dynamic range. Some ADC's have built in programmable gain amplifiers, or high precision sigma delta converters, if they are low noise enough, can make use of the lower order bits to give "gain".
This is just a very broad summary, the papers in the links I gave you go into more detail.
If you have no electronics skills, you will need to buy what you need, there are too many things that can go wrong if you don't know what you are doing.
cheers,
Richard
