Silverfast's HDR mode is just their fancy way of saying they output the raw scanner data into a 48 bit tiff file, without any modification. This feature is identical to Vuescan's scanning as a slide, and setting your output to either 48 bit RGB, 64 bit RGBI, or 16 bit greyscale. You will get the same data.
If you want to use Silverfast's Negafix on the "HDR" (really RAW) files you need Silverfast HDR. If you have Photoshop, or another photo editor that supports levels on the individual RGB channels and provides an invert function, you can do the Negafix work yourself, but it is a bit of a pain.
If you have Photoshop you can also use the ColorPerfect plugin which does essentially the same thing as Negafix. But in my experience, Negafix is pretty darn good.
There is also a free software package to do color negative mask removal and inversion, but I've never been able to get it to work.
With your basic package the biggest thing you are missing is multiexposure. Vuescan does more than your version of Silverfast, but Silverfast's Negafix is better (though limited to working on 8 bit per channel output).
For B&W, you shouldn't care about any of the Negafix stuff. You just need to invert your "HDR" image (which is just a tiff image with raw scanner values) in your favorite photo editor.