Sawadee

I'm confused as how to use my visa, l have a 2 entry visa which stated to enter before 20 Dec 2009, l entered on 17 Nov 2009, they stamped it valid until 15 Jan 2010. My question is how do I get the most days from this visa, when do I have to leave and reenter to do have max days. Thank you for your help.

You have to make your second entry on 19 December, obtain 60 days and extend for 30 days.