Hi Emma
As the good people above have already mentioned, report it your insurance company asap....If they ask why you've left it 5 days, just say you've been in shock since the accident, which is true really, as it does affect you......... The other driver is trying it on and blackmailing you, as she knows was her fault and saying it was yours......Let the Insurance companies sort it out and make sure you give a full detailed account of what happened.....Good luck, Emma.