High Potassium Level

My doctor's nurse called me yesterday to tell me to come in right away for my latest blood results, from Nov. 26, 2008. My Phosphorous went up to 5.6 (normal is 4.5), and my Magnesium went up to 3.2 (normal is 2.5). But the emergency was for my Potassium level, that was 5.9 (normal is 5.3). 6 and above is very dangerous and can stop my heart. An EKG was performed and it was ok. The doctor said I can either go on dialysis or take Kayexalate for 3 days and see if my Potassium lowers. My next blood test is on Dec. 3. She also added a new (this makes 3) blood pressure medication, Atenolol 50 mg, because the first two haven't been able to control it anymore. I just have to watch that it doesn't lower my heart rate too much because taking it with my Nifediac can do that.