The picture brightness control will be in the Samsung TV setup menu. There is a setting for brightness, but there may also be a setting for the backlight (my Samsung has that, anyways). Both will increase the brightness of your screen.
Yes, you should have a remote for the TV, the blu-ray player, and your digital box. If you want to consolidate, you can purchase one of the Logitech Harmony remotes and control everything with a single remote.