Someone can Can Someone Help Me with My English?

I thought before I could speak English but in fact I cannot.
For example, I never studied the language consciously I just watched movies, played computer games and read what I was interested in, role-playing games book, for example.
So my English was improving continuously but I should have realised my knowledge limited to understand. By now I can understand nearly everything that I reed read or even I hear. On the other hand I cannot express myself properly, my English is full of grammatical mistakes. So that is what I want to change, that is why I am here. I started studying the grammar on websites such as britishcouncil.org. I have been reading "Animal Farm" from Orwell, which is a really great readings in my opinion, and a very good practise at the same time.
But again I feel that I understand what I read but I am not able to saying or writeing my own impressons as way as theye are as the way they are.
But I will not give it up, "practice makes perfect" as the proverb says.
I would like to ask for help for this, any advise are welcomed!
Thank you very much for your help!