Joseph Jagr wrote:
Can I download this version in lieu of Lightroom 6 or is there another solution short of getting a new computer?
A new computer is your only option to run LR 6.
I don't know if the a LR 3 is still available, but if a download exists you can't use it. Because the serial number that you get for LR 6 can't be used with LR 3.
You have to change your operating system to Win7 64bit or higher.
In addition to what others already said: Your new camera will probably not be supported with LR3. This would need you to convert to DNG with the free converter and then import the DNG into LR.
Adding to the above.... you spend good money for a top range camera and use an obsolete computer to drive it??? Interesting priority.