Canon and concept art suggest that prosthetic arms that can hold blades or shields or contain crossbows are possible, though being able to move fingers and grip like a normal hand would probably require a combination of engineering and magic that hasn't been seen yet and would need research. What she has coming in would depend on what sort of expertise and resources Furiosa has access to before joining the Inquisition, because average citizens probably have to make do with peglegs and hooks and such and nicer versions would require contacts and coin. At the very least, she can definitely get something more functional through RP once she's with the Inquisition.