As Telexan said you can flash the bios for an upgrade for free but if you need a whole new chip thats a different story. To flash your bios you'll need to go to the motherboardsmanufactures webiste and find the right bios and flash utility. To get a new chip you can go to
http://www.biosworld.com/ I've never used them you may wish to find someone else. The chip will come pre programed for your board and you have to install it wish can be difficult.
here's another site
http://www.biosman.com/
oh and welcome to techimo