Hi, you could clean the wheel in a ultrasonic cleaner and probably fill the cracked spokes with brazing and then as NDIY fit a new tyre by shrinking or using some high strength cylindrical retaining compound, which would be easier if the wheel is not too difficult to remove, or like Bob has said, fit a new wheel, but failing every thing else, if you have the skill, making a completely new wheel set would probably make it an economical repair. Like NDIY, I'm not going to buy it, so it won't bother me either.
Regards Nick.