I want to get a new processor but what else do I need?

I play video games and I know exactly what processor I want, it has the right socket - size etc. It's an i5. I was wondering if I need anything else in my computer though... I want to get the processor to play more powerful games (possibly something like battlefield 4) but do I need to get a new video card? Graphics Card? I cannot afford to go and buy anything over $250 atm. (That's why I'm going for the I5) So please don't just tell me to go out and by another computer. I'm not going to spend $700 extra on a brand name. All I want to know is if I need to get another thing or some other upgrade in my computer so that I don't overload or break anything. My computer is a laptop.

Computer Asus X550C

My specs - RAM - 8gb - CPU - Intel Pentium ULV 1.8 Ghz (see? It's a little to weak for some hard gaming and work.) I have the standard Intel(R) HD Graphics Everything is unchanged.