That is not possible to copy the OS over. There are some tools that do this but the chances of it working would be more of a hassle than just reinstalling the OS.
Backup your files and install the SSD. Remove the HDD. Go into the BIOS and boot from DVD or USB. Make the SSD next boot device and go through the steps to install the OS on the SSD. Then you can install the HDD and format it and use it as a second drive.