I am working on L1A and my Visa and I94 expires on 13-April-2013. Right now I am planning to go on a vacation to India and return before 13-April-2013. I would like to know if there is a minimum number of days with active visa I should have before 13-April-2013 to get into US?
No, as long as your passport is valid for 6 months and the visa remains valid you can apply for entry into the US and if there are other problems will be granted into the US as long as the visa is still valid even on the same day.
I agree with Haroen. As long as your passport is valid and meets minimum travel requirements of the country you are traveling to and your visa is valid upon your return, you should fine.