By my calculation it'll bring it up to about 10.3/10.4%.
Having reread your posts you say you might not have mixed the wine thoroughly. If you followed the kit instructions and added the right amount of sugar you might still get to the desired 12%.
If the sugar wasn't dissolved properly it would give you a false reading, on the low side. However, the sugar would still be in there and the yeast would still find and convert it to alcohol.
Did you measure the amount of water you put in? What are you fermenting in? Does it have gradations to say roughly how much is in there?