You had better take a speaking course at a language center. Be sure to choose an approriate level so that you don't have to learn many things else but focus on improving your speaking ability. A course of an American teacher is highly suggested, although teachers from Australia, England are also not bad for a begining student.
Don't worry if you can't understand what the teacher say, don't hesitate to ask for a repeat, and don't mind if you speak gramatically incorrectly. The first matter is to loudly and proudly speak your English out. You will have time to amend your speech later.
Good luck.
p/s: thank you for asking in English, it has been quite a long time since I last wrote in English, hihi