Help Advice in enforcing a dissolution of joint ownership of a property in Spain

I am in an awful situation but I want to enforce a dissolution of joint ownership with a once friend, who refuses to sell and has no way of buying my half. I know this is costly and we face to loose everything but I want out of having any association with her anymore....my power of attorney has been used without my knowledge and consent to take money out of my Spanish bank account by my solicitor and friend.
What are the costs and how long does it take to enforce, and where would I go to, to start the process as I need to do this as quickly as possible.
HELP