Hi again alicia, i think you are very confused. The time here, is good for nothing. It doesn't matter how long it takes you to go upstairs, whether you can do t in 3 minutes or 3 hours is irrelevant, the work done is the same. You must approach the problem in a different manner, let me try to explain:
When the energy of a body changes, that energy change must ahve come from somewhere. If at some moment, a body A has more energy that at an earlier time, that "extra" energy it has, he must have obtained from something else, this means, that some work had to be done to the body A in order to grant him that "extra" energy.
When you go upstairs, your energy increases, more specifically, your gravitational potencial energy increases. This increase in the potential energy occurs because of the work done, which means, the increase in the potential energy is equivalent to the work done, this is:
W=\Delta E=E_f-E_i=mgh_f-mgh_i=mg\Delta h
In this way, you can relate the work done, with the energy difference. As you can see time plays no role in this whole thing. You must think of the problem in terms of energy changes.
Another comment too. This equation you mention W=\vec{F}\cdot\vec{d} is true for constant (or average) forces only. Since this is not the case, you shouldn't use that.
Hope you understand a little better now. If not, ask again.
