Got any pics of the damage to her car?
You say you have a witness who was in front of you? Are they fighting your corner or agreeing with hers? Where did her witness see the accident from?
As Matt said, the insurance company will sort out who's fault it is, but you have to push them to fight your corner. If you're 110% she was completely in the wrong, and there's absolutely nothing you could've done differently to avoid or prevent it, then tell your insurance company it. Write such a detailed report on what happened that it leaves absolutely no questions to be asked. If you haven't had to do this for the insurance company yet, do it anyway, while it's all relatively fresh in your mind so you don't forget anything when it comes to filling out forms. You'll have a copy then you can go back to and add if you remember anything whilst waiting for the insurance to sort out taking your statement.
I'm sure your witness' story will collaborate with yours, but if it's someone you know, get them to do the same, and make sure your stories match up almost perfectly.
If they try and offer 50/50 fault, you may be forced to accept as it won't be in their interest to keep fighting something they don't care about and would be happy to accept half liability so they're not spending anymore money on it. Do you have any legal cover on any policies? I have it on my RAC and got a proper solicitor appointed to me after my accident (other bloke admitted fault though, so all she had to do was fight for my compensation), but they will do all the hard work for you if you do. Couldn't recommend it enough.
I've been through all this malarky before, so if you haven't and have any questions, drop us a PM
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