Hi Jackie,
What Doug is saying, with the SG you now have, you need to raise it to 1.085 now. You may be confusing "raising the SG" with "back sweetening" which is taking a dry (i.e. no sweetness) wine to semi-sweet or sweet. This latter process is done after fermentation is complete and after the wine has been stabilized with Potassium Sorbate.
Simple syrup (it's really simple) is made from two parts sugar and one part water. Put the water in an enameled or stainless steel pot, add the sugar and stir, apply the heat to dissolve the sugar, but do not boil it. Allow the syrup to cool and add it directly to the wine and stir it in well. Now, as to how much to add, there is a way to calculate the amount but a more direct way is to add about a half cup, stir and take a hydrometer reading. See how much the SG has increased and that will be the approximate increase per half cup.
BTW, I just made some last night and four cups of sugar and two cups of water yields right at 1 quart of syrup. You can store the unused syrup in the refrigerator for about a month.