I don't think creating a new software is a viable solution when you are in need of money.
The key to doing well on these sites is to spend the time to prove to potential clients why you're worth paying a higher rate. The best way I found to do this was to ask lots of questions about what people wanted, describe in detail how I'd go about solving their problem, and do my best to show that I really cared about building them what they needed, not just what they thought they needed. I did all this before I would quote them a price.
It's also key to be choosy about what jobs you bid on - you'll need to spend at least an hour per job you bid on, so you'll want to make sure to choose ones that are going to be worth your time.
Lastly, view jobs that you get through these sites as interviews. I found that once I'd done a project or two with people through the site, we usually were able to work out an arrangement where they just paid me directly by the hour for further work. The money I made outside of the sites with established clients was by far the majority of the money I made.
If you can't design yourself, perhaps team up with someone that can.
Good luck.
Remember, there is dignity in every form of work, and you can learn something almost everywhere.