Hard to say - you should expect it will be difficult.
French takes quite a bit of time to learn. CLB 7 may be possible in a year to a year and a half - provided your studies are serious and concentrated. This means not just studying casually on your own time - but also attending classes for that year - as well as dedicating time each week to speaking French with others who know the language or are studying it.
The short answer is that it's possible - but will take considerable time and effort.
