I'm not sure that you can replace your graphics card on a 17 inch HP laptop since most uses onboard video instead of PCI-Express graphics card like desktop computers.
You cannot replace or add a video card to laptops with integrated graphics. Very few have dedicated graphics cards and even then it is a pain to replace.
I know there are External video cards for laptops, but I think they might be kind of bulky, and expensive in some cases, and you can't use it if you are away from home.
Like mentioned above, there is no PCI express slot for laptops. You would most likely have to get an external one to use - which as mentioned above, could be ideal just expensive and - well it's external. Usually gaming is dealt with custom computers, not really laptops.
Now, with that said, SWTOR (I have it and love it) is not very GRAPHICS heavy - kinda like WoW style graphics. With this said, you want to make sure your CPU and RAM is good enough to handle the multiple changes and rendering, not so much the graphics. I suggest you install it and run it first to test and see if you even need the external GPU for your system.
