prashanthrangu

It has been said that Krishna delivered the knowledge(i.e bhagavadgitha 5000 years back?).How can i assume 5000 years from now?(considering we are in 2005 how can i assume 5000 years back?). 2) krishna belongs to dwaparayuga but it has been said that this kaliyuga has passed 5000 years and yet 4,26,000 years should pass.Is this true?When he has taken form of Lord venkateshwara?