You need help for 2 things based on your request.
1, you need the app to be downloaded by many people - this can be achieved in 2 ways, paid method through
http://welcome.freemyapps.com etc just search google for more. The other way is free but requires efforts and time, a website might be needed including seo marketing.
The first way is very fast but does not retain but the second way is very slow and retain in as much that your app is good.
2, You need investor for your app - i am sorry, i do not know of any.