But if you are going to go with a snub, I would stick with .38s and be happy. I don't think there is a significant real world difference between a .38 and a .357 from a two inch or less barrel, but in my hand at least the .38 is noticeably more controllable, and especially in a lighter frame. If you can adequately control a .357 snub, more power to you (and in that case I'd look at a .44, if you want a bigger bullet), but anything you can do control-wise with a .357 you can do better with a .38.
The one thing that would drive me to change out the snub you have is the ported barrel. I am sure it helps with control, but for self-defense shooting see it as a liability. You don't always get to extend and arm much, if at all, and in fact the snub is precisely for up-close-and personal shots. The problem with a ported barrel in these cases is it can direct case and bullet shavings into your own face. I have seen this happen. Also, if fired from a pocket (another snub specialty) you again have gas and maybe fragments going in a non-productive direction.
What I would suggest is get two non-ported snubs with shrouded or concealed hammers and put one in each pocket.
Oh, and the knife is very good too. Just make sure you train vigorously in accessing it (as well as your snubs), and if it is a folder, getting it unfolded. ("Vigorously" includes having people in your face pounding on you or kneeling on your chest as you lay on the ground.)