You can't really improve your motherboard. Also, can you elaborate on what your graphics card is? Like, the Vendor and the model? Is it a PCI graphics card, or AGP?
Ultimately, the motherboard you currently have has quite a few limitations. You might be able to play some older games, but nothing recent unless its something less complex. You may be able to run emulators for older platforms, like the PSX and Nintendo 64.
MSI 870S-G46 | AMD Phenom II X4 965 @ 3.8ghz | Gigabyte Radeon 7870 Ghz Edition | 1 x 128GB Kingston HyperX SSD | 2 x WD 500GB Blue HDD | Arch Linux x64 | BFG Tech LS SERIES LS-550 550W | 2 x 4GB DDR3 1600 RAM, 2 x 2GB DDR3 1600 RAM (12 GB)