Can you list the full specs, including the case and psu, of your current build? Don't include anything you plan to buy.
Edit: Nvm. Didn't see the link lmao. You definitely want a discrete gpu. If you're looking at around the ~$90 range, the Radeon HD 7770 is probably the best choice at that range.
However, I would highly advise buying a better case and psu first. The case is flimsy and low-quality, while the psu is just plan out low quality. If you don't plan to upgrade the case, which I recommend, then at least upgrade the psu. Then, you can grab a 7770.