The weather feature was added in 2010 along with the GEN6 NAV system. XM became standard in 2010 and was paired with weather/traffic updates at that time.
If memory serves me correct, you can only add XM OR the Vias ipod interface on the pre-10 models. They both use the same port on the back of the radio so it's one or the other.You can still add XM to your vehicle and it will interface with your unit. Also you can update your Ipod connect to the new unit in about 5 minutes and 30 bucks from VIAS technologies. It changes the charging output to 5v vs 3v so your Iphone will now charge.