Nice Shooting, especially for off hand!
I have put several hundred rounds thru my Ranger 103 over the last couple weeks. Mine is basically the same rifle, but made for sale thru Sears.
If you are missing that rear elevator, it may be for a reason. Mine consistantly shot about 5" high at 50 yards at the lowest setting. Perhaps your previous owner just got rid of it. You may be able to find an elevator around at a good shop, but then you'll have some compensating to do. I am slowy compensating with a file to the rear sight. Getting better.
To get your groups more to the left, you can let off of the screw that holds the rear sight to the dovetail ever so slightly. Then you can move the sight ever so slightly to the left with your fingers and retighten the screw. Fire a few groups of 3-5 rounds and see how you did. If you need more adjustment, rinse and repeat.
Good Luck
Ew, edit, I thought I read the front sight was tacked. Nevermind