It is quite likely the rear derailleur itslef is bent and needs treplacing. THe steel 'claw' type hangers that are used on entry-level and dept. store bikes without built-in hangers are usually much stronger than the derailleur attached to them, and so the derailleur usually bends or breaks before the hanger.

However, a new derialleur with a built-in hanger will likely cost ~$15 - $20 and this will most definiately fix the problem.

THE PROBLEM
THe problem was likely caused by an improperly adjusted derailleur - the 'L' limit screw on the derailleur should prevent you from beingf able to shift into the spokes, but since it din't I would expect its maladjustment was the cause. You didn't say - were your injuries a result of a bike accident? Becuase often derailleurs gent bent slightly in a crash and this can also cause the derailleur to get caught in the spokes, even if the limit screws are set properly.

I suggest you buy a new derailleur with a built in hanger and a new cable and follow the derailleur installation and adjustment instructions on parktool.com