yes, that is the BEST part about owning a blackberry...you can upgrade the OS
did you download DM 4.3? if not, uninstall the current DM and reinstall using this link:
you have a pretty new OS
look here for latest, greatest:
you cannot send or receive email, browse the internet, or use PIN messaging without a data plan (and that's a Blackberry data plan) ... you won't be able to send MMS (picture messages) either without a bb data plan.
card size, 2gb for now. i think i read you might be able to get a 4g working with the newest software loaded...
welcome to pinstack