Question Card Suggestions or Recommendations

[c5d]

I have I believe it is a custom built micro itx computer that I got t a thrift store for $7.99 and it's in an Antec-ISK 300/350 case and has an Asus AM1I-A motherboard.

So I know I'd need a half height low profile card and a single fan or heatsink card.

But since it's a decent little machine I'm just looking to turn it into a small Steam Machine.