Its a complete waste of money to upgrade that.
$200 is better spent on a new system
This Newegg combo here for $233 would run circles around that single core athlon64 and would actually even let you game some. That athlon64 would barely run facebook. Now I'mnot saying buy this kit, just that tehre are way better options out there than trying to upgrade that 'coffin'. its dead - throw it out.http://www.newegg.com/Product/ComboBundleDetails.aspx?ItemList=Combo.956680
Or you could just upgrade your motherbd, cpu , and ram - if that case will take standard parts.
a8-3850 + motherbd - $150http://www.newegg.com/Product/ComboDealDetails.aspx?ItemList=Combo.987531
4gb ram @ 1866 (best speed for a-series processors) - $35http://www.newegg.com/Product/Product.aspx?Item=N82E16820148559