So you made 2 transactions in 1 min and now you say that your wallet automatically sends coins to another address? Impossible.

Did you encrypt your wallet with a password?

The only explanation could be that you have been hacked and somebody stole your wallet.dat and if this is the case there is no way to get your coins back.

If I were you: unplug your machine NOW from the internet! Backup all your relevant data and wallets etc. Do a fresh OS install. Install good security and never use this computer to surf weird sites anymore when you also store wallets on it.

Also encrypt everything with different passwords.