Unfortunately, with Laptops, it's almost impossible to change out your graphics card, especially if yours is an integrated graphics card. I had a Lenovo laptop for a while and struggled to run the Sims, unfortunately, you can only upgrade memory (and only in some cases on some laptops and not by very much) as the rest of the laptop is usually complete.
So, even if your laptop had a separate graphics card that wasn't integrated, you would need a very, very specific card that would need to fit in a very specific size of slot.
However, upon looking up your computer, you have a secondary graphics card that's in there, but I'm unsure of how that works, or if that's even the right laptop you're using. I'll wait for someone who is more aware of that kind of knowledge to give the final verdict.
In most laptop cases though, you simply can't switch out parts.
Edit to say I found this:
http://forums.lenovo.com/t5/IdeaPad-Y-and-U-series-Laptops/V570-Switchable-graphics-applicable-for-switchable-graphic/ta-p/479237Hopefully the tutorial will help you determine if you have a second graphics card within your laptop that you can turn on.