For the last version of PHP I didn't found RPM's. But you can try compiling it by your own. Maybe you can find the RPM's. Then "rpm -Uhv new-php-ver.rpm" .
I found them for MySQL here
. Download them and again "rpm -Uhv new-ver.rpm" . You have to download all rpm's needed.
To see which one are installed on your box "rpm -qa | grep mysql" and for php "rpm -qa | grep php" .
If you have "yum" installed you can just use "yum upgrade php" and "yum upgrade mysql" and it will do everything for you. Also "aptget".