Joomla java script required ASAP

I require a function for my site, that pops open a box that says CLosed on Mondays - only on Mondays, it must look up a world time server, query the time, calulate the time for thailand, and be closed according to the times we are closed. This wil be all day monday, and after 10pm on every other day. the script wil be connected to two buttons, one on the order main navigation button, and on the checkout button of the cart. THe pop up will be the same as out existing pop ups in the site, with a close button etc on the top right. Budget is around the 80us mark.