Unfortunately, subscribing to the RSS feed only feeds page posts and don't also include comments or when someone posts on your Wall.
I did run across this application today that you can use which will send you a text message notification when someone posts on your Page. However, standard text message charges from your carrier apply (which probably isn't a big deal if you have an unlimited text plan.) But from I saw on the application page, they also send out ads via text message to users and some other advertising. They have plans to come out with a Pro (paid) version but that's not out yet.
Basically, to me, you get the ability to receive page notifications by text but they get access to and all your info via their application. I don't really think it's worth it.
You can find the application here:
http://www.facebook.com/pagenotifications and check out the FAQ tab for more info.