Ok thanks,
1.) and what about security, so nobody can hack my wallet
or
2.) even worse when my hardware brakes or my software getting problems, then i lose my money.
Al least read about people losing their mined bitcoins after problems with their hardware.
1) Mining hardware is not directly related to the security of your wallet. In order to protect your coins, you need to encrypt (password protect) your wallet directly from the bitcoin-qt program. Your S3+ mines does work for the pool of your choice, and the pool sends your address the earnings. Your S3 and your wallet don't directly communicate with each other.
2) Every time the difficulty increases, your S3 will earn a little bit less. If your S3 breaks completely, and you can't mine, then hopefully you bought form a manufacturer with a good warranty.
2b) If you're talking about the hardware (PC) that your wallet is on, then yes, it is possible for the HD to crash, and you lose your coins. To prevent this, always have a backup of your (encrypted) wallet.dat file on a USB drive, other computer, or heck even a CD/DVD.