If you have been advised bladder replacement surgery then i am assuming that your cancer is invading the muscle layer (in the biopsy report) and it has not spread to any part of your body (bones/lungs/liver). Also, the neck of the bladder should be free from disease else this surgery is not recommended. If that is the case then you need to get the surgery done at the earliest and not wait for 45 days as the tumor may spread even before that. It is a major surgery and carries a 5-10% risk of death depending on your health and the expertise of the surgeon. Besides this, complications include bleeding, infections, urinary incontinence, impotence, pneumonia. in expert hands and in properly selected patients it gives a 75-80% chance of cure to the patient. You will need a month on an average to recover