I went to the court house in London and plead not guilty on a speeding ticket 30 over on the 401. She said things will be sent in the mail. What is being sent in the mail? And how long is it suppose to take already been 3 weeks.

Wait another 3 weeks

As you filed your Notice of intention to appear for trial, the clerk will have to process this request and set a trial date. It usualy takes a while. As soon as the trial date is set you will be mailed a "Notice of Trial" advising you of the date and time for your trial.