You cannot flash your bios to an apple one, that is totally not possible. You have an Athlon board, the sata bus that is usually used is an Intel one with device id's for Intel that the Apple kexts can recognise. You are going to have to get a PCI sata card I think. Do you know what kind of onboard Sata chip you have? Do you have the option to run the Sata as IDE in your bios.