For (1.), I'm assuming you entered the number of cycles of loading for the model in the Fatigue study. If so, the "life plot" should show the "life consumed" at that stress level. Example: if you loaded with 100,000 cycles at 20,000 psi stress, and the s/n curve lookup shows life at 20,000 psi is 1,000,000 cycles, then the plot should show 10% of life is "consumed" (100,000/1,000,000). Does that make sense? I believe the legend may show "10%" as 0.10.
For (2.). I'm not sure the request to plot a new s/n curve makes sense, since it's fixed by definition for that particular material (i.e, it would have been entered by the user). Perhaps you mean something else. Can you elaborate a little?
You may also want to take a look at Miner's Rule (Linear Damage Rule); It's listed in the solidworks simulation documentation as the method used to determine how cumulative damage from a cyclic load affects the life of a part.