Sarah has been under development for over a year, and the programmer is very confident of its release soon. I can't be more specific than that at this time, but I will give an update the second the app goes to Apple and the Android Market for approval.
Absolutely! A lot of apps fail because of insufficient traffic. The funds raised here will be used to promote the app, increase traffic, and hopefully make this app catch on. After release will be the most important time to have money for marketing.
You can, and you should. But if your really love this idea, why not both? Buy the app for yourself, and give the code from Kickstarter to a friend to help spread the word!
Plus, giving the support here will help fund the marketing efforts sooner- versus a slower cash flow, and less word getting out, this is much better!
The radio will give you weather, music, news, etc. But only at a specific time, a specific station. This app on the other hand is completely customizable. Plus, you get the added benefit of it reading emails and customized public transit notifications.
Don't see the answer to your question? Ask the project creator directly.