External Video Card

I have a Dell Inspiron i7559-2512BLK, and I have a big doubt, I would like to know if this type of laptop can be adapted to an external mediant case that sell amazon, but I have realized that they need a port type thunderbolt, but unknown that my laptop has it, so I would like to know why the person or an expert in laptop assembly gave me a clear idea, since I am excited to buy an external case and mount a card to give a little more power to my laptop , I would like your help and give me clear explanation, what method I use or what they recommend me