Other than continuing to pursue this with the police the other option you have potentially is in defamation of character. If you are identifiable in the posts and the posts are untrue and have the effect of making right minded people hate or ridicule you then you may be able to claim in defamation of character if you suffer a financial loss as a direct result of the defamatory remarks. This means that if you lose your job as a result of this you may be able to sue for the money you lose as a result.
You cannot claim for anticipatory damages only for actual losses and it does cost a lot of money to make a claim (tens of thousands of pounds) so at this stage it is not worth claiming.
There is no harm however in writing to her to say that you consider her actions to be in defamation of character and if she a) does not remove the offensive posts and b) continues to make them and you suffer a loss you will have no option but to sue her.
You could see a local solicitor who can write a letter on headed paper, they may ask her to sign an undertaking to say she will remove comments and refrain from making them. The effect of a breach of undertaking amounts to a contempt of court. Obviously you will have fees associated with this so it really is up to you at this stage whether you want to go down this route but it is certainly an option for you.
If you have any further questions about it please do ask. Otherwise all the best and I hope you can put a stop to it.
Hello is there anything further you would like to know about this?