This logic that since we are poor country we should not help out others is actually is very stupid, no offence.
Our budget is 240 billion $ every year.Our economy is 4 trillion $. The problems we are facing is nothing to do with less money for development. It has more to do with the faulty distribution of the resources to the needy.
So a billion $ aid to other poor countries(who by the way are our neighbors and their problems will affect us in one way or another) which will be spread in years will have a little or no effect to our economy. So even if we stop the aid and focus that money in our economy it is not going to affect any more than it already is because as i said our problem is not with the resources but its allocation and corruption. But a billion $ to our neighbors like Myanmar or Afghanistan or some african countries will come back to us in much more than one way. Not only will we win some points among local population but also help our indian companies to get deals easily which by the way will help our economy. The govs of these countries will also be invested to help us in more than just supporting our projects but also help us by going after any anti-india elements based in their counties(eg: Myanmar).
This by the way is a very smart diplomacy and a very shrewd economic and political move