That's a bit of a messed up build but we can fix it for you. What are you doing with this computer? If it is for gaming I suggest you get a better GPU than a 750Ti as those are really not very powerful. You won't be impressed with them. I'd suggest going with at least a GTX 970 or an R9 290.
Please let us know what you plan on using this computer for so we can put a list together for you.
The cables are included with the parts you buy, as are the screws. All you need to bring to the party is a magnetized phillips head screw driver.