abacab
The Cakewalk Studio Instruments - String Section is something you already have.

 I messed with those and I was surprised how decent they sound in a mix.  I'm one who doesn't really care for authentic string sounds unless I'm doing orchestra.
 
 GPO is also a good alternative. Easy to set up and use. I used them in a disco project and they seemed the best over more authentic huge strings like EW and VSL.
 

Thank you for your ideas.
 
Dumb question: I'm presuming that all of the above will work alongside and inside SONAR X3, right...?
 
Thanks...

They are all available as 64-bit VST, so should run just fine in Sonar 64-bit, or any DAW that supports the VST standard.  Any version of Sonar from the X-series to Platinum should be on the same playing field with plugins.
 
Some plugin developers have started to support 64-bit exclusively, and dropped support for 32-bit plugins.  That is a good reason to be running a 64-bit DAW today.  Sonar x64 can bridge 32-bit plugins, but I always try to use 64-bit if available.
 
Edit: There is also the matter of VST2 or VST3, which I didn't mention.  But since you are on X3, that shouldn't be an issue.  Sometimes you'll have a choice of which to install and use. Occasionally one works better in a particular host DAW or system than the other version, so you'll just have to try them out.

Sidroe
On the affordable side, I recommend Garritan Personal Orchestra or IK Multimedia's Miroslav 2! I have others that are more pricey but those two still get used a lot.

Sidroe
On the affordable side, I recommend Garritan Personal Orchestra or IK Multimedia's Miroslav 2! I have others that are more pricey but those two still get used a lot.

The miroslav is good but the samples have like a delay of some kind. I have zero latency with everything else.