Womens' frames typically have shorter effective top tubes. Your wife's fit on your bike seems to be consistent with that. You can certainly get a shorter stem, and also a taller stem -- that will help bring the handlebar closer and raised up. You can move the saddle closer to the front of the bike on its rails (unless you've already done that). You can also replace the bars with those with more upsweep or backsweep to position the grips closer for her.