I'd disagree that one is in some way inherently worse than the other.
Both are awful, and while rape victims face many awful things to overcome, much of that is due to societal attitudes towards the victim of such crimes, rather than the horror of the act itself. Rape victims, instead of receiving the same empathy and compassion as the those affected by murder (such as the family/friends of the deceased), are treated as if they were responsible for the actions that occurred against them. This, more than anything, is a reason for rape to be "worse" than murder, but of the two crimes themselves its impossible to impose a hierarchy upon them.
In terms of legal penalties handed down to perpetrators, it makes some sense that murder faces harsher penalties than rape - the ending of one's life against their will is considered the worst crime one can commit, compared to any other crime. There are still living victims of a murder, with the crime impacting on the lives of those who knew and loved the murdered person, but perhaps the impact of murder is less than the impact of rape upon the actual victim - after all, one is left alive to suffer while the other feels nothing at all, being dead. Having said that, as much as society does not want people to rape, it wants them to kill even less...
Sorry, I'm rambling... Summary, both are bad, its impossible to say which is worse, and its a waste of time to try and apply a hierarchy to suffering.