I want some help studying English.

I have decided my mind to study English so I'm looking for some helps here.
I think I have got some choices but I can't determine which way is the best for me at the moment.(Well, there might be no best way below.)

1. Just listening to a radio or a conversation continously.
2. Study with a book of grammar or words.
3. If it is good, buy an app.
4. Do 2 or more ways together.

Well, I thought yesterday that I would search a book at the book store and buy if it was nice but I have found "Essential grammar in use" as an app at the android market today evening and also found it is cheaper than the original book. That app might be a help?
Or just hear the radio with my phone could help me enough? I'm in confusion so I want some help. Any recommendation? I also will listen to other ways if they are.

Here are my situations.
1. I spend about 4 hours for going and coming back from school. I can hear anything just what I want to.
2. I'm almost exhausted after I've got home so I'll never study anything at home.
3. Actually I have little time to study English while I am at the laboratory.
4. I am very weak at grammars and words.
5. I don't want any method if there are both English and Korean together. I want English only.