I don't know about stopping the turtle but in the wind you described, you should be able to get it out of the turtle yourself and back up again. If you couldn't get it out of the turtle then maybe your mast has water in it. If you get to the stern of a hull and pull with your righting line the bows should come up, then fall over to the lee side. You end up with the mast into the wind and the wind helping you to right the boat. If you travel the jib on the down side all the way out and pull on the jib sheet (without cleating it) the jib will trap air and help lift the mast. It is better if the boat is turned at that point so the mast is angled off the wind a few degrees. As the boat comes up let the jib sheet go and get to the other side so it doesn't just keep going over again. I would leave the jib uncleated and sail in on the main.

Howard