Where can I download the 1.2 version?

Unfortunately no, your cards are too old. You need a card with a compute version of 2.0 or higher, for instance my GTX460 has a compute version of 2.1. According to this page here your cards are version 1.1:

https://en.wikipedia.org/wiki/CUDA

You might be able to use Octane version 1.2 or earlier ...

I have 2 EVGA 9800 GT running with SLI. Whenever I try to render with octane, it always says "No CUDA Device Selected"!

bepeg4d wrote:Hi,
sorry but your card is too old, it's even older than octane itself
you need at least a Fermi 5XX+ card for working with octane, kepler or maxwell is better
ciao beppe

Will my 9800 GT with SLI work?