Laptop fans are not like desktop fans, they need to fit in small spaces and need to move a certain amount of air in order to meet the heat removal spec of your laptop. No small feat as a laptop has confined spaces that make this difficult.
Try ebay
http://shop.ebay.com/items/_W0QQ_fromZR46?_nkw=toshiba+a15+fan&_sacat=0&_fromfsb=&_trksid=m270.l1313&_odkw=toshiba+a-15+fan&_osacat=0