There is nothing you can do to get the coins back unfortunately. Due to the way blockchains function and private keys work once coins have left your wallet nobody can control those coins except the person who controls the address they were sent to. Unless you can hunt this person down and force them to give it back. Definitely buy a hardware wallet and keep your funds split up to mitigate your risk.
RE: How I LOST +$500,000 in A SECOND! (HACKED)