Lowell, I'd just keep the welder you have right now for a bit. A new welder wont make any difference if you dont practice and learn how to prep the material for welding etc. I'd buy some various "farmer" rods and some grinding wheels, some good clamps and some good safety gear. Make sure you have the right number shade in the helmet, Some good gloves that fit good instead of cheap heavy gloves that you cant work in.

 Then,....burn holes in the atmosphere. Start just laying beads on a piece ground clean scap. Try various settings and various positions to see how it goes and make notes. Try some heavy stuff with a gap, then some thin stuff at a right angle etc. See if you enjoy welding enough to want to do it more often. If you only plan to repair stuff, just keep the welder you have as you wont be using it that often. If you like to weld and get used to it, you might start making little projects that help make your life easier aroud the shop or house. Then you can justify a new(er) welder with a few bells and whistles.

 IMO.

 But youtube has some really good instructors and it makes welding so much more enjoyable when you are not fighting with it all the time. Preparation or the work is key.