motherboard

how do i know what motherboard i have. when i look into the case, i see SiS-5565, but I cant seem to find the bios upgrade for that number. will a bios upgrade let me choose more bus speeds in my bios? the only bus speeds i can choose from are 66 and 100. i want to overclock my slot-1 celeron 333a, but it doesn't post at 500mhz, so i want to use a bus speed of 75 or 83. my motherboard also comes with a SiS 6326 vid card BUILT-IN. same with the sound card (cmi 8330 with C3D) can someone help me???