I just bought a new computer. Graphics/animation is blurry and I'm not tech savvy. HELP!!!

Kicking myself, I should have went for an expensive model. I just thought great price $600, brand new. Looked at the 8 RAM and 1TB thought it was good enough. Didn't consider the processor and graphics card. I did download my Sims 4 and the game launched saying it didn't recognise the video card. Maybe I can take it to a computer specialist to add better processor? I don't want to take it back as I already downloaded stuff on it and set it up. Can you install a new processor/graphics card in the tower?