Try the drive on a sata II port, and if you aren't happy with the results then look for another option. I highly doubt you will feel the need to add anything other then the ssd even if its on a sata II port.
The vast majority of the OS and Applications is random 4KB so unless you're copying large data (e.g. Video files) back and forth from one SSD to another SSD the SATA 2 300MB/s is more than adequate. One of the primary things that makes SSD's 'fast' is its low latency (0.1ms SSD vs 12ms HDD).
So simply plug the SSD into one of the (4) Intel SATA2 (3Gb/s) ports, and be happy.
The problems with 'SATA Cards' is that they're often non-bootable and a PCIe 2.0 x1 is max 500MB/s and when shared the max is typically ~380MB/s per port...so I see no upside and instead see it as a waste of your money.
had my sataIII drive in a sata II slow before and the computer is still super snappy. in fact now on sataIII and i really dont notice the difference. in the past i used a rosewill rc-225 with ssd attached as boot drive.
note that when you install another sata controller card, your computer will take a few seconds longer to boot as it has to post the card also (basically flashing another bios screen at boot).
id agree with whats been said here, dont waste your money. your comp will still be very fast.