You have emuNAND and sysNAND confused. Gateway supports emuNAND up to 10.5 (10.5 didnt break anything so they didn't have to make a new release) and sysNAND up to 9.2. SysNAND is your real system, emuNAND is an emulated system that you can keep up to date to let you use the eShop and play newer games, and you can get one once you have Gateway or another CFW running already. So, you are out of luck as your sysNAND is too high.
However, Gateway are working on having native support up to 10.3 in the near future. So hang onto your 3DS and don't update it, and you should get something eventually.
Edit: you could also downgrade to 9.2, but that is risky. Depends how patient you are. If I were in your shoes I would just wait and see. The point of near risk-free downgrading has been and gone (since 10.4 was released) so it will be just as easy to downgrade later as it is now. Maybe easier if Gateway release something super stable. Or if something better comes out of the scene (but I doubt that, I think the scene's done all it can in terms of downgrading).