Being mostly fluent in three months is a very ambitious goal. If you truly want to achieve it, I would reccomend enrolling in an intensive language program that offers immersion classes and homework daily. This isn't a goal that is achievable with a tutor in a few hours a week. Best of luck to you.
I would like to add that if you need only more or less fluent "survival" language, it is possible, but under special difficult conditions: regular sessions with a tutor daily for about 3-4 hours minimum and a huge amount of homework in addition.