The free versions are what they are and not supported. There is never an update for LE. They just release newer versions as time goes along. I have X1LE. Far as I know they never release what was called X2 or X3.
Your versions best asset is you might be able to use it to get a big discount for the latest version.
LE versions are just very basic and I found it was mostly the missing plug ins that made it worthless to me. But I used it to upgrade which was a value of around $100 so not bad for free.
There are many free DAW's out there that will probably out perform Sonar LE 2005.
I would look into purchasing Sonar Artist. Or try the demo.
I got my Sonar LE with a Roland A 49, it's probably the newer version of yours.
The keyboard will always work with the MIDI port.
And USB drivers are still posted. They are probably the same ones I'm using.