FSP Group FSP450-60GHS(85)-R 450W Micro ATX12V 80 PLUS BRONZE $64.99
i believe that will be the right size, looks like the same as what is in your case now. pickings are slim in the ITX and microATX sizes. i am not familiar with FSP like seasonic, corsair, antec . .ect.
this does give you a 6 pin and 8 pin PCI power connectors. you could get a card that uses either for 150 and 225 watts max but not both
which would be a 300 watt card.