If it's only a wobble, say up to 10mm deflection as you spin the wheel, all you need is a spoke key (and they come in various sizes). You can leave the wheel in place and use the brake pads as a guide to the deflection and how tightening spokes is affecting the deflection. You don't even have to take the tyre off.
Essentially, tighten spokes that will pull the wobble back into line. Take it a bit (say a quarter turn) at a time and you'll be amazed at what you can achieve. You only need a tension meter and a dish tool to build wheels from scratch. If the nipples are seized then you'll have a few challenges, but simple tensioning should get you home.
I had the same problem, thought that sorting a wobble should not be that difficult, and it isn't. I went on to build a wheel and that's done >1000 miles now with no problems at all. Very satisfying!
Have a look on YouTube and see Mickle's Tip of the Day at the top of this Forum.