Just happened to be putzing around in the gear closet. Mine is probably 6 years old but I think it's the same model. 12' 6" (150") with 9 sections.

You might be outa luck, ie, you've either got to spend the $ for the new poles, or, look around for a used half dome and scavenge the poles. Craigslist, garage sales, or, go to a REI used gear sale, where there are usually half domes. Just check that all the poles are there and in good shape. I think those might be your only choices. Good luck.