I couldn't find any previous version for your BIOS - only the 206 version is offered by Asus and other third party websites. I suggest you try asking Asus support to see if they can provide old BIOS versions for your laptop directly.
Also, it seems that your processor is an AMD Turion 64 MK-36. Running a recent operating system will be almost very difficult even if you upgrade the RAM and use a SSD. Windows 7 (or a lightweight Linux distribution) seems to be the last system supported by your laptop.