How many books would you recommend me to read per week to improve my English?

I am French and I speak fluently English(I spent 10 years in the US). However My English is not really sophisticated as you can judge from my current writing. I am back to France for good so I have no way to practice & speak on daily basis English . I was told to read a lot of books in combination with audio books. I was promised that it would allow me not to lose my English but with chance it could eventually enhance my spoken English. My question is how many books should I read per week? I was thinking at least 3? Thanks for your input .