As per clause 3 (b) in your residential agreement - 'The Resident acknowledges that the Room is furnished with the Furniture. The Resident may not add any additional furniture, furnishings, or other items requiring an electrical connection or heat source or furniture over 40cm in diameter (including heaters, electric blankets, cooking appliances, lights, extra beds, mattresses or armchairs) to the Room without the approval of the University (which must not be unreasonably withheld).'
Should you gain approval from the University please be aware that you'll be required to pay a removal, storage and/or disposable fee for the existing furniture.
If you have any further questions, please don't hesitate to contact us at accommodation.info@sydney.edu.au.