oh no... i worked so hard for them
An expensive lesson then.
can i get them back somehow?
Probably not. Unless you can somehow get the hacker to return you the money which is darn near impossible.
can i find him?
You can try to analyse the address that it was sent to. It will be extremely hard.
how can i find the malware?
You can use an anti-virus to scan it. The only thing I'll recommend is to wipe your computer and change every single of your passwords.
This. Either clean your pc and check all your startup items or wipe your drive. You at some point downloaded malware. The criminal behind this then stole your 3k worth of btc. =(