I do not have a lease with my landlord who is my sister. I was just informed her condo is going up for a short sale. Do I still have to pay her rent since I have new moving costs.

You are considered a month to month tenant and must pay rent if you are living in the unit. The owner must give you proper notice to vacate, most frequently 30 days. If you want to leave then you too must give 30 days notice from the first of the month. Short answer, yes. Short sales can easily take many, many months and may not be approved by the lender. Your moving expenses are not considered any type of unusual hardship since you'd have to move someday.