just use card reader n copy all form 1 gb card to 2 gb card [ copy from 1 gb to pc n then paste from pc to da 2 gb card ]

about SMS those r saved in da sim card n it dont matter if u change memory card [ untill u passed all on da memory card ]

if u cange da cell then u need to connect cell to pc n transfer all contacts n sms on da pc n use it again on another cell