Buy (or pirate, but really, you should buy them if you can afford it, they’re great) the entire set of Pimsleur French tapes. There are 90, each 30 mins long. Do one tape every day. Note that this will take you longer than 90 days as you are supposed to repeat tapes when you don’t remember ~80% of the content.
Concurrently, get Anki (flashcard program) and find a French vocabulary deck ordered by frequency. Learn as many new words per day as you have time for. Do all your required reviews every day.
Concurrently, spend as much time as you can every day reading or listening to appropriate material and trying to understand it. Search for “French graded reader” for some good books to buy.