You ovulated around 5 October 2008. Theoretically sex between 1 October to 6 October could have gotten you pregnant. More likely however between 3 October and 6 October with the most likely date 4 October 2008.
Depending on your luteal phase length, this can move forward 1 or 2 days (3 to 8 October with the peak fertility at 6 October 2008)