Can I adjust the cooking time and temperature for my braise?
This answer may be too late for you, but in general a braise can be done at a lower temperature as long as the food doesn't stay in the "danger zone" for too long.  See this answer for more information on the danger zone. 

For example, this recipe advise to have the oven at 300 F for an and hour per pound.  In the tips section, it states that the author sometimes drops the temp to 250 F.  

Braising is fairly forgiving and is typically a method used on tougher cuts of meat, so going slightly longer shouldn't be a problem.