Your English is not bad. It's pretty good.
I myself had studied English in ILI for seven years. It depends on your goal. If you want to learn English in a standard way don't attend the conversation classes like Kish. Because in conversation classes they tell you to memorize different dialogs in order to be able to handle a simple conversation. But when you learn how to make sentences yourself then you can speak as fluent as a native American. My suggestion is that you forget the conversation and focus on learning from the foundation. Here in Iran there are two institutes that teach English in a standard way. First one is The ILI ( Iran Language Institute - کانون زبان ايران ) and the other one is National Language Institute ( موسسه ملي زبان ). I urge that you attend the ILI classes because all of their books are written in America but the NLI's books are Iranian.
I hope I haven't bothered you.
Thanks