What you need to do first, in order to even show an investor that you have a chance at being successful, is to first be successful at selling softweare for others.
Focus on Affiliate marketing of software from Clickbank, Avangate, et al, and then search for whitelable software PLR software if you can find any.
After success in those areas, you won't need an investor for your software idea, as you should have enough to finance your first software development project and be successful in marketing it.