My Potassium Level Is 5.9 And I Need To Gave

My potassium level is 5.9 and I need to gave surgery on the 25th of this month. I've been trying to eat low potassium foods and my levels are still high. They won't prescribe me sodium bicarbonate. My dietitian said for me not to eat fruit. Please tell me what I can do to lower my levels. Thank you