if you have to renew both, the you have to go to the immigrations first to get your residencia renewed.
then to the JCE for foreigners to get your cedula renewed(you have to show your up to date residency to get cedula renewed).
JCE Extranjeria is open 7 days a week, (1st of january is a official holiday, closed), i dont know the opening days/times of the Immigrations office.
Mike