Motherboards And Processors

Well, I am here again and I want to be more precise in what I want done and how I want to update my computer. The following is a list what my computer has and I need help in what I can do to update it.

Motherboard:
CPU Type AMD Athlon XP, 1266 MHz (12.5 x 101)
Motherboard Name Gigabyte GA-7VKML(-P) (3 PCI, 1 AGP, 1 CNR, 2 DIMM, Audio, Video, LAN)
Motherboard Chipset VIA VT8375 ProSavageDDR KM266
System Memory 768 MB (DDR SDRAM)
BIOS Type AMI (02/24/03)
Communication Port Communications Port (COM1)
Communication Port Communications Port (COM2)
Communication Port ECP Printer Port (LPT1)

My AGP Slot has already got a Sapphire Radeon 256Mb Graphic Accelerator that is only 4x. I need to update, BADLY!!!