You are talking about going from A2 to C2 in 4 months. Unless you are already at or very near C2 in all other skills, meaning your low conversation skill level is due to delayed production or something, I would say this is impossible. 

If you change the question to "how can I improve the most in 4 months", I can answer you, but I'd like to know what your current level is in all other skills, and how much time you have per day to work on it.

you should watch english movies with subtitles and repeat after them . and listen to english songs and sing with it . the more you practise the more you'll get better . 

remember some rules of the english speaking like 

reading --> readin' 

good day ---> gooday

left behind ----> lefbehind

remember the differnce between (B) and (P)

and so on , 

just practise .

Find people to speak to, and practice everyday....regular and consistent practice is the key

try to communicate with your circle friends in english in each and everyday....good luck

Dear Aegis anfd Amin.

If you don't mind, Could you help me make a plan to promve my english skills. I think all of my skills is A2 ( like you say Aegis), and i really want to be better. i have 2-3 hours per day to study english. i will do my best.