In order to answer the question 'is a Masters worth doing' I think you need to be a bit more specific with your long term aims. 'A better career' can be a bit of a vague thing to be aiming for, particularly in the current economic climate. You also need to be clear what 'better' means: more money/stability/stimulation?
If you want to work in research, then you could go in as a research technician or maybe research assistant without a Masters. But if you want to do a PhD then you would need to do a Masters, as you wouldn't get funding with a 2.2 alone. But if you don't want a research career then this might not be the best route for you.
Don't do a PhD primarily because you want a 'better' career. Do it because you're interested in research and the topic you're working on. It will drive you nuts otherwise. As far as Masters courses go, you also need to work out what you would do, and why - this is important both in terms of making your application, and ensuring that your Masters makes sense on your CV.