That kind of rim damage indicates over-worn brake surfaces. Whether you should replace the whole wheel is a strictly economical question which is hard to answer in general. Wheel building services and components prices differ in different countries; somewhere it is cheap to rebuild a wheel at a mechanic; somewhere buying a new wheel is cheaper.
Given that you have an "old" wheel size, less popular spoke count, and a wheel that has been in long use (meaning it may also have worn hub bearings and tired spokes), I'd recommend buying a new one.