A broken nose repair is best re-set in the first 2 weeks after the surgery. It can still be reset at any time after that as well. It's important to make sure that you have an examination of the internal and external portion of the nose and address any deviated septum that may be present internally as well as a nasal fracture.
I would recommend seeking out a qualified surgeon for a formal evaluation within the next few days (facial plastic surgeon, plastic surgeon, or otolaryngologist/ENT). Typically, because of the rapid swelling that often occurs, any type of intervention is deferred until several days out after the initial injury. Closed nasal fracture reduction may be possible and would potentially help correct any acute deformity. This is typically performed within 7-10 days of the injury. In cases where a closed nasal fracture reduction does not correct the deformity, a more formal rhinoplasty can be performed at a later date. Good luck!
You may want to consider bypassing the ER (if it was only your nose that was injured) and call a plastic surgeon today. It is typically better to fix this in the first week or two after the injury.
You should go the the E.R. as you are planning. Your nose will need to be examined and possibly some x-rays taken to determine what sort of treatment you may need to repair your broken nose. It sometimes may be possible to repair the nose with a closed reduction, where no incisions would be needed but the nose can be placed back into the correct position. You will have to speak with the E.R. regarding your insurance.