Listening and speaking are almost always harder than reading and writing. Don't worry^^

Tell her "너도 영어 좀 공부해라." - "Study English". haha. I think taking a Korean language course. is the best way to build your basis. I took a English-Speakiing course for a year. and I think it builded my basic stuff.(Pronunciation, Tense. etc.) As Richard said, there are bunch of resources in the internet. If you have the basis, you can learn anything. You can also use italki answer. :)

There is no shortcuts to understanding a language. The more foreign the language is to your native language the harder it will be to learn. The only way you can understand and speak the language naturally is to have lots of experience in reading, listening and speaking. Thankfully we live in the internet age and there is almost unlimited resources available to learn your target language. As for listening and understanding you should be exposing yourself to Korean media, whether it is movies, TV shows, panel discussions. By doing this you should naturally improve your conversation understanding ability.