Time of release; unknown.
Will you have to buy the new version; yes.
Why do you have to buy the new version; because its an entirely new platform designed to run in 64 bit, with quad core computers (up to 4 computer cores or perhaps more) and using as much RAM as you can put in your machine. The platform had to be totally rewritten and at this min, it is still being rewritten, thus its not ready. Hopefully this year.
This will be like going from from a Volkswagen Beetle (1970's) to a Corvette, but with Prepar3D 1 to Prepar3D TURBO.
No more staring at jittery low frame rates....
Perhaps they should call it Prepar3D Quad or perhaps P3D-Q (quad core computer useable).