If I file for emergency bankruptcy to stop a sale ,how much time do I get until the bank lifts the stay and gets a new date?

It depends. The bank might possibly not file a lift stay motion at all. And it also depends on what you are trying to accomplish.

You will have 14 days to file complete schedules and a plan, failing which the court will likely dismiss your case.

That timing is completely at the discretion of the lender. Some will request relief quickly and others may just wait out the bankruptcy process. As for how long after relief before a new date is set, that depends upon your state foreclosure laws and possible where they were in the process at the time you files your bankruptcy case.

It is difficult to predict how a bank will act without more information. In some cases, the bank files a motion for relief from stay within the first 30 days of the bankruptcy case. This is more common if the property is commercial. In other cases, however, the bank waits until the bankruptcy case is closed (the automatic stay terminates upon the earliest of dismissal, discharge or the closing of the case) to resume the foreclosure action. Depending on how much of a priority the foreclosure is to the bank, the fastest I'd estimate that a bank can obtain relief from the stay and have a foreclosure sale reset is approx. 60 days.