I say there is no way you can do it quickly, but you might be able to do it in a year.
My advice is:
1) Find a book, a good teacher, or a website that explains English phonetics very well. Learn the nuts and bolts of English's sounds thoroughly. For example, do it until you can hear and pronounce "word" vs "world", "bit" vs "beat", and all such things distinctly.
2) Find sources of good texts and audio. Read, read, read, and read, And mix in some listening on the side, especially news casts. You do it until you can read Economist, Time, and other magazines and literary books comfortably. Once you can do this, your listening and speaking will have improved remarkably.
This is my experience. I think there is no substitute for the above. Most other methods will cost you more while taking much longer to get to the same point.