Sykes was breath tested at the scene and blew 631mg of alcohol per litre of breath - the legal limit is 400mg.
The police then found a plastic bag on the wheel arch of the car and a second bag under the car. In them were small bags of dried cannabis containing a total of 21g of cannabis. Sykes admitted one plastic bag was hers and said the cannabis was for her own use.
Defence lawyer Andy Schulze said Sykes immediately told police she had been driving and was co-operative and helpful.
Mr Schulze asked that Sykes, who had no previous convictions, be given a fine rather than community work so she could move to Perth to work in the mines.
"She has been up front from day one. The court should reward that honesty and integrity," he said.
"It would have been easy for her to hide that [she was the driver ]."
Judge James Weir refused, his request saying Sykes had started to show a pattern of behaviour involving drunkenness - from the "unflattering situation" where she obstructed police arresting a male on July 14 to driving drunk and being in possession of cannabis.
The police investigation into Mr Jack's death is ongoing.