1. https://support.hp.com/us-en/document/c05296965
This is a SLIM LINE case without much space or power.
2. There are no card slots to install another graphics card.
3. That said all you can do is to make do with what you have. For example you can max out the RAM and install a SSD and then leave it be.
Hi I'm new to computer and i just brought a hp slimline 260a129 and I'm looking to upgrade to play games. It has amd radeon r5 graphics and a amd a8-7410 processor. What would be the best graphics and processor for a round 100 dollars?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic