Gallaxy S3 recharging prob-Master reset? will I loose contacts?
Yes, a master reset will wipe your downloaded apps and personal data.

You could backup your photo's on your PC. Another option would be Google Drive or any other cloud service.

Your contacts you can open contacts under settings. There should be import/export option. Then you can export them to your sim card or what every option is available. Also another option that maybe available is to save them to your Google or Samsung account.