Hey Kates,
Back again on this end.
I agree with the last poster about the .44 being the way to go, and for all the reasons he stated and more.
However, if you choose the .357, I would personally go with the GP100 in a 4" stainless model.
It carries very well. In a left side/butt forward holster it is out of the way for right handers - even if you are carrying a rifle/shotgun/shovel/posthole digger etc. on the right side.
As I told you in the post about Blackhawks, Super Blackhawks etc., I have owned and used those models in times past.
Now however, I own only Double actions - other then autos - and am very well satisfied. The Ruger double actions are tough guns. My regular load in my Redhawk is a 310gr LBT cast bullet ahead of 19grs. of AA#9.
As Timex used to say, " they take a lick'in and keep on tink'in."
I carry my 5 1/2" Super Redhawk .44 in a left side Butt forward holster just as I do my well used 4" Security Six .357.
Because of the size and carryability/concealability of the GP 100 it would be something to keep even when you advance to the .44.
If you haven't done so already, you need to do some reading/thinking about some quality reloading and casting equipment. Cast (WW cast bullet cost is very low) and load your own and you can shoot a bunch more for the same money and quickly pay off the investment of equipment.
Keep em coming! :-)