Getting high and low values from between 2 hours and 3 hours ago

In a cBot, how can I get the highest value and the lowest value for a symbol from between the time period of two hours ago and three hours ago?

protected override void OnTick()
{
    Print("The lowest value of the symbol between 2 hours and 3 hours ago was: {0}", ????????????? );
    Print("The highest value of the symbol between 2 hours and 3 hours ago was: {0}", ????????????? );
}