A quick fix would be for you to restrict your salt/sodium intake for a week before and then take diuretics the day before and the day of the weigh in.
There are natural diuretics too but not as effective as something like Lasix.
Also you have to watch you don't deplete your potassium level.
And I would definitely runs this by your doctor before you did it to make sure it is safe for you to do.
HEY you said a "quick fix" and I am just thinking out loud here...