yes.. I can understand how difficult to study on your own. yes.. I've also same experiece when I decided to study in English. only speaking. In my case, I had a good reading skiil and listening skill. but I wasn't able to speak and write fluently. I was't able to even find a penpal friends. I've also studied in english on my own. and then.. I finally singed up for the converstion course at English language institute.
well... If you aren't able to take some conversation classes, how about write a letter on italki writng practice. If you write what you'd like to say to penpal friends, some Korean people may reply it.
When you write this, please say like that " I'm writing a letter to you guys. so Please, reply to my letter in Korean! "
Maybe, I think that you can get the good results although you don't have a specific penpal friends.!
I hope it helps!