That depends on yourself Pouria. If u wonna bag an almost definite entry, study hard for 2 months and then work on previous IMAT tests and choose Naples university. with an average score of 20, u should be able to do it. but my advice is not to rush it. do your best and go for a better university. if u wonna put ur life in medicine, do it properly. 

non Eu student visa procedure is after the admission or their must be pre enrolment