You couldn't upgrade the GPU on it even if you wanted to and it came with one as they are almost always soldered onto the motherboard. The only way to upgrade would be to put in a new chip with the newer HD 5000 or 6000-series graphics, but those are on newer chips (Broadwell, Haswell) and will not work on your older laptop's Ivy Bridge motherboard (and not to mention would be extremely expensive to buy).
Hate to be the bad news breaker, but the HD 4000 is what you are stuck with if you want to keep that laptop. :-/