1. Will Intel SSD 520 work on this board, (and is it worth it , since it wont run at its full potential)
Yes, the SSD will work. You will not get the advertised speeds from the drive but real-world performance will be much better than your current HDD setup.
2. Can i get a PCI card to run the SSD at full speed?
Yes, you can, but you would have to spend more than if you had just bought a new motherboard and cpu.