Yeah, I'd probably go for a new rim.

Then again, I hate throwing stuff away. Take it over to a bath tub and see if you can bend it straight over the edge. If you can get it to w/in a couple mm, go for it. Your thigh might work too.

Note also that your reference surface is not flat. If you have access to a stationary table saw, the machined table surface makes a great flat. If you can't get to a table saw, try rotating the rim 90 degrees all the way around, and flipping it. Make sure the spot you think is high, is actually high.

Figure out where the bow in the hoop is and and bend it from the middle.