Check your pc and make sure you clean it as has been suggested to you. I would advise you to shift your coins to another wallet. I have been suggest you coinbase or xapo but just search here and you will find many details of wallets. Make sure you change your passwords, and i hope you have not used it on a public pc. Be careful with your btc.
Using an online wallet was the problem in the first place why use another one? Use a desktop wallet and if you must have an online wallet in the case you need to buy something while you are out of your home then keep only what you are going to spend that day and if you don't then send it to your main wallet.