When can I expect to know my correct weight after lipo?

Thank you for your question and I can understand your concern.  Despite the removal of your breast implants, liposuction will cause a fair amount of increased body weight as a result of swelling.  You should see your body start to rid itself of most of this water weight within 4-6 weeks of surgery.  Hang in there, I do not think that you need to adjust your intake at this point.  

You don't need to change anything. Maintaining excess body water after surgery is normal. As healing progresses this will be eliminated and your weight will drop accordingly.