I am not able to find the case "Zebronic Zeb-28R" online. Looking at the other Zebtronic products available they all seem to be pretty big. Unless you can find a URL for me with the case I would say go with the GTX 750ti I linked to you. All you have to worry about with that thing is if your case supports a dual slot GPU. To check you can just open up your case, and decide how the GPU will fit into there. Length shouldn't be an issue with the GTX 750 ti, but you mine as well check that too. However, the GTX 960 is a whole different story. This GPU is quite big and you will have to check length to make sure it will fit.
You probably won't have to do any of this stuff though, as it's rare a case won't fit something as small as a GTX 750ti in a small form factor. If you can take a tape measure and measure the dimensions of the case, and you can tell them to me, that will help me narrow down just how supporting it is of big hardware (mid atx, full atx, micro atx, etc.)
P.S I see that Zebtronics only has made 1 ITX case, which should be the only one with the chance of a GPU not fitting.