Update for Fedora 18:
You can install the kmod-staging package from RPMFusion repository:
sudo yum install kmod-staging
Old way (on Fedora 16 & 17):
In order to install the driver for SD card reader, first download it from http://ubuntuone.com/p/153B/.
After decompression, change to rts5139 directory and install the driver:
make sudo make install sudo depmod
Reboot the machine and you are done.