As the title says, I don't think quest 5 is possible within the amount of time given. I'm level 52 with two days left, and it took 2-3 days to get from 51 to 52, meaning this just isn't possible unless:
1. you complete quest 4 to spend real money on the game (and even then you may need to spend more) - this sort of defeats the entire point of Gamekit for me, and others I'm sure, as the reason I'm here is because I don't have spare cash to spend on games.
2. you keep levelling up while waiting for quests to complete/run out - but if you don't know what the goal for the next quest is, this is dangerous, as you might over-level and then have your screenshot denied.
I think the final quest needs to have a lot longer for the time to complete, as this is the first time I've encountered a quest on Gamekit that simply isn't possible within the timeframe without spending real money.