Well, if you have a tripod then go for the lowest ISO possible (ISO-200), if you are taking a landscape then anything over f/8 will probably get you a decent enough DoF and in low light the tripod will allow you longer shutter speeds without bluring.
Simply mount the camera on the tripod, frame your shot and with an aperture of f/8 or higher, focus mid way through the scene. The camera will tell you in the viewfinder what exposure will be right so just alter that using the dial until you get the correct exposure shown. Probably better to put it on a timed release so you don't knock it.
Take a shot, check the histogram for blown or underexposed areas and adjust to suit
I don't think I would do a great deal to the first shot in PS, it seems fine to me