I have the same problem, a shitty bar. I'm looking to do something about it, but until I can, I go with what I have.
Honestly, while I believe that quality bars are important, I don't think they are THAT important in the grand scheme of things. If you want to train, you can train with anything. As long as the equipment doesn't put you in danger, it's useful enough. Does your barbell give you the workload you require, without putting you in danger? If yes, then I say it is getting the job done.