I have Sony Vaio VGN-FW455J laptop .. and its battery is not even lasting 40mins ..So I am looking to buy a new one .. and probably a bigger one with better mAh .. Current one has 4400 mAh ..The current battery model is VGP-BPS13/S .. So I just wanna know if any 9cell sony vaio battery will be compatible with my laptop or I need to get this specific model only?Anyone have any idea wht 9 cell battery models will be compatible with my laptop?