Graphics Card Upgrade for Dell Inspiron All In One 24 3000 model 3455

Hi, I'm new to owning this All In One Dell, and while it has a quad core processor, I have noticed that it is lacking in the graphics department.  I know this unit is quite slim, and am not sure of one's ability to open it up and upgrade specific components inside of it.  It comes with an AMD Radeon R4 integrated graphics card, so my question is if there is any way to buy a better card to put inside of it.  Thank you in advance!