If you believe that you have been wrongly convicted then your only option is to appeal to the Crown Court.. The same is true if you wish to appeal against the sentence.. Were you represented by a solicitor? If so ask them to get this up and running for you - having first asked their advice as to whether or not the sentence was fair in the circumstances.. If you represented yourself then you will have to go back to the court and ask them to assist you in making an application.