Thanks for all the great responses. I understand more about tension now, thanks PhantomCow2. I'll work on the wheel tonight and get things a little more even. Thanks too everyone else for the responses about rebuilding the wheel. For now I can't afford to have it rebuilt, but I will instead have it rebuilt when I have the money. For now I have to make do with getting the tension even.
What is a good price for rebuilding a wheel like this?