Thoughts:
1) We could make better suggestions if you elaborate on the challenges you are having now.
2) Raising the bars is quite possible, but I recommend thinking about how you want to change your torso angle/shoulder position and then think of the optimal hand positions that go with that.
3) Consider both the height and reach. Keeping the arm angled down reduces the tendency for you to pull yourself forward off the saddle on the occasions when you have to pedal hard.
4) Consider getting a tall quill stem adapter like the Nitto. That allows you to shop all the modern stems rather than being limited to tall vintage stems.
5) If you move away from drop bars, don’t overlook the touring bar option. These have a sweep angle that many prefer over a straight bar and offer a wide range of front to back hand positions that suit different riding work.
6) Also worth considering is raising the bar with a tall stem adapter and switching to a modern drop bar with shorter reach and drop.
Lots of ways to keep this great bike working. 😊
Otto