Your property value is based primarily on the condition, updating, and desirability of the house. The garage, while an important piece of the puzzle, is the last place I would recommend putting your updating dollars unless there are structural or esthetic issues that might be a negative to prospective buyers.
The orientation of the garage is probably the third rating criteria (behind size and condition). A driveway may be a plus to one Buyer; the next will think only of the shoveling! You will likely not see an increase in your property value by reorienting the garage - all other things being equal.