That's fine...I run Drupal7 here without problems on 5.2.17
php-gd and php-mysql both exist at version 5.3.8-4 and 5.2.17, please check again. What do you mean 'doesn't work'? doesn't install?
Please provide the output of 'rpm -qa | grep php | sort'
yum --enablerepo=timb-testing clean all
yum --enablerepo=timb-testing install php-gd php-mysql
EDIT: Glad you have it working