PPCLI Mcpl, Never tried Rossetta Stone but have you seen these yet from OEF...language survival kits that have a collection of mp3s as well as a guidebook. There's one for Pashto among others. I've used the Modern Standard Arabic one and it's not too bad although there were quite a few errors in the guide, improper spellings/words in arabic script so I'm not sure if the pashto one will be the same.
http://oef.monterey.army.mil/downloadlsk.html#P
good luck, let me know how you make out as I'm curious about their products as well!
cheers.