i have a column with date and time(column A) and i want to roundup the time to every quarter and then separate the date(column B) and time (column C)

A B C
3/14/2006 10:43PM 3/14/2006 10:45PM
3/14/2006 11:34PM 3/14/2006 11:45PM
3/14/2006 11:52PM 3/15/2006 12:00AM

note that since 11:52PM rounds up to 12:00, i want to change the date to the next day.