will the points i have got in the demo ver of 2142 carry over to the full game
Possibly, but I doubt it.
I'd have to let someone else comment on it though (too lazy to research that :P )
The points you get during a round in the demo will not be added to your soldier's stats.
If you were refering to the beta as the "demo", then the answer is also no. All stats from the beta were erased.