Even a little heat that late in the game won't really do anything. it's quite common for most of the fermentation to last two or three days and trail off to almost none for the next five. Stick to the plan and you'll be A-OK
A great man knows that he knows NOTHING
Actually, that was the same kit I did for my first batch. It only bubbled for about 3 days and then ceased.
Life, Liberty, And The Pursuit of Hoppyness