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Joe before you invest in a new radiator make sure your timing is actually okay.
Your wrote in your first post that you thought your timing "seemed okay". Maybe re visit the timing again just to be absolutely sure. Timing can make a huge difference.

You've also posted that you have been shutting it down when your temperature gauge has reached 180 degrees. Take the cap off and place a dial meat thermometer directly into the coolant. You can drive with the cap off and with the thermometer in place. That way you can pull over when your dash mounted gauge reaches 180 etc... and check to see if the gauges agree.

Go ahead and keep driving it after reaching 180 and see just how hot it gets.
With the cap off you will see it starting to steam and boil over before things get too serious and damage your engine. (if radiator is too full it cam mimic an over heat / your gauges will tell you if that is the case) Just stay close to home and be willing to pull over and rest the engine for a bit if it actually does start to get too hot and boil over.

One more thing to check is for a failed head gasket. Remove the fan belt and watch the coolant for bubbles when revving the engine some. The kits to test for compression gasses in the automotive parts stores or online are fairly inexpensive and leave pretty much no question if you do or do not have a compression leak.

I think that there's a reasonably good chance you won't need to spend the money on a new radiator.