When I try to set the reminder for a task, the maximum I can set is to remind 3 days before when I would need for some tasks at least a week, like the web application
Due to the smaller screen size, we haven't included the longest reminder times for relative reminders on Android.
However, you can always use absolute reminders - instead of being reminded a certain time before the task's time, you can choose to be reminded at a specific date and time and simply type "every Friday at 2pm" or "20 Sep @ 13:30" and a reminder will be set to this exact time.
You should adapt the window then ;)
By the way I have a Note 2.