Yes. You definitely need to work on this problem together and come up with a solution. Under no circumstances should you get married without fixing this problem. You will both end up being miserable. Worst case scenario since you say you enjoy each other's company and like talking to each other etc. is that you should aim to become 'just friends'. However, she will carry this problem into her next relationship as well and it's unlikely to cure itself on its own. Some people are just less outwardly affectionate than others though and if you are just not compatible in that way and it's not something she thinks is a problem that needs to be worked on you have a problem on your hands.
If you both value the relationship and want it to improve you really might want to consider seeing a sex therapist to help her work through her issues with sexuality in the wake of the assault. You'd see a doctor if you had a broken leg, wouldn't you? It's wise to consult a professional if you have a problem like this too. Or, if that's a bit too much you could try to find a Tantric Sex workshop somewhere in your area. Tantric practices usually focus initially on just holding each other and building trust and intimacy with your clothes ON. This could be a good first step? If she's not even willing to consider doing something like this with you it's time for a major rethink.
"The only thing to do with good advice is to pass it on. It is never any use to oneself." - Oscar Wilde