XM Satellite radio dies several times a week

I have a 2007 Prius with option package number 6. Until recently, due to myself being an avid Sirius listener, I was using my Sirius Starmate in my car. Now that I can get the best of Sirius on XM, I decided to activate my factory XM radio. Several times a week, I will be driving along and the XM radio dies; if I press the AM-SAT button, all I get is AM radio. Everything else (6 disc CD, AM/FM, and iPod through the aux port) works fine. Turning the stereo off and on doesn't help; the only way to get the satellite radio back is to turn the car off and then back on. This usually happens when I am on the freeway during my commute so obviously, I can't just power-cycle my car when this happens. Being as I have a long commute and this happens several times a week, this is getting really irritating. I seem to remember an interview with Steve Wozniak where he mentioned having this problem with his 2010 Prius but it didn't say much more than that. Do I need to go back to my portable radio or is there something that can be looked at here?