Are you taking offline classes? You could find someone to teach you and ask for an intensive class, so you can learn in a shorter time. When I first learnt Korean I finished level 1 and 2 (TOPIK) in a month because I took classes every day during term break.

First, you probably should get an assessment test on all four sections. Reading, listening, writing and speaking. If you're coming for a short time, you'll have to read and listen to a lot of Korean. Focus on those, then speaking. I'd say your best bet would be finding a real person to talk to, for example on italki. Also, enquire at a nearby university for Korean classes. There are online resources like duolingo, but the Korean-English course on duolingo isn't complete yet so be aware. Good luck!

Hi~Nice to meet you on italki.

I am Korean! Hope to be good friends :D