while this might be the case - there is also the possibilty the size / fit of the bike is appropriate - but the bar height is too low
which is not uncommon (and unfortunately too common) - especially older bikes with a short / cut steerer
note how many newer bikes are now equipped with a longer steerer and spacers (obviously excluding bikes with one piece bar / stem)
OP states that she needs about 2" more stack. The bike doesn't fit.
A riser stem is unlikely to get her that much additional stack because of, well, trigonometry. And even if it would work, it's a hack for an ill-fitting frame.
The bike was not a "steal." It was wasted money.