Short answer: No. You don't transfer the existing OS to the SSD; conventional wisdom at this time is to do a fresh install.
Yes, it is possible to install some of your apps to the SSD and others to the regular HDD, but you will still have to re-install them, not just run the old copies off the HDD without changes. Installation makes changes to the registry and possibly files in the Windows directory; very few apps are designed to be "portable," requiring only their installation directory structure to run.
How big is your OS partition or, if your drive is not partitioned, your Windows and Program Files directory? Heck, you can buy an SSD the size of your hard drive for eight hundred bucks. What is your current budget?
Finally, unasked-for advice. Unless that WD is a Green drive you bought to keep power usage down, replace it with a larger 7200-RPM drive to improve overall performance.