DataTable question

I have a datatable that correctly populates from a SQL query, but I want to do a couple things with the datatable itself. First I want to only grab the rows that have a date of today or previous in the column "ECompletion", then I want to sort those by oldest date and finally push the results in order to lbl_urgentTasks.Text.

{
dtTasks = getDataTable("SELECT * FROM Tasks WHERE IsActive = 1");

\\NEW CODE HERE
}

Anyone know where I can start with this? I have searched online and didn't really find an answer. I have good experience with c# and the .net framework so don't be afraid to go crazy!

Okay so to start with, I sorted the dt using a modified SQL query "SELECT * FROM Tasks WHERE IsActive = 1 ORDER BY ECompletion ASC". This gives me all active tasks ordered by earliest date.