2 things are needed for building your immune system :

1. Nutritious Food – Make sure that you have a healthy diet consisting of Carbohydrates, Protiens, Fats, Minerals & Vitamins
2. Exercise – Begin with 15 minutes a day and take it up to an hour every day for 5 days a week.

This will surely boost your immune system within 2-3 weeks.

I am not sure about them but you can surely send gifts to India anonymously through GiftstoIndia24x7.com. I have been using them since a long time and they have never failed me till now. The best part about their service is that they are available 24×7. So no matter which time zone you are in – they are always available.

History says that Nathuram Godse killed him. But I think its his ideologies which a section of the society was not able to digest which ultimately led to the assassination.