Unless you are seeing problems with the current running of your computer, there is generally no reason to upgrade the BIOS. It's good to remember that a failed BIOS install can break the motherboard so that it's un-fixable. Yes, if you're going to move on to a different operating system that requires a new BIOS, then it's a good idea to get the latest and greatest. But if things are running fine now, don't fix it if it ain't broke.
That said, if you need help, then you'll need to tell us which motherboard you are using and which version of the BIOS you already have installed. Once that's known, there are paths you can take, if you wish. You can visit the motherboard manufacturer's site and get their latest BIOS and instructions on how to flash the BIOS.
Hope this helps.
Grif