See
How do I reset my message counter to clear, or zero? - BlackBerryFAQ wrt first question.
On second question, seems when a media card is included with a new BlackBerry it is 2GN, if that's what you are asking. See
What type and size Media Card can I use in my device? - BlackBerryFAQ to maybe see your options.
Posted via BlackBerryForums.com Mobile