All you have to do to install an RPM is:
rpm -i packagename.rpm
Though in this case you are actually doing an update, so you would use the -U switch:
rpm -U packagename.rpm
As for rebooting, the only update that will ever require a full reboot on a Unix system is the kernel itself (and even then, there are ways to load a new kernel from an existing one without powering down). Just install the package and set the time via NTP or however you are handling it.