The first thing to note is while you can make minor enhancements to a scanned image, post-scan manipulation should not be relied on to save an image - GIGO (Garbage In, Garbage Out).
The second thing is that slide/film scanners are not simple plug 'n' play devices (regardless of what the manufacturer might say!) - sure, you can get them up and running easy enough, but optimising the various software settings to get the results you want, on your particular film, can take quite some time. I would consider a couple of weeks, not days, necessary to get everything in tune.
Thirdly, is your monitor calibrated? A mis-set monitor will can make the best scans look crap!
That said, you must be brutally critical of your originals before you look at the scanner. Are they really accurately exposed and sharp? Or do they just look ok on the prints? Study the negative/slide with a loupe - a film scanner will only emphasise any deficiencies in the orginal.
Assuming you have a good original - and I would strongly rcommend using a good portait shot (lots of flesh tones for colour balance checking) with bright highlights and shadow areas - both the highlights and shadows should be as bright/dark as possible without being totally white/black (ie. some detail should be visible). Use this as a test image.
Unfortunately, I don't know your scanner or its software, so can only make general suggestions.
Lack of "brightness" is usually indicative of too low a gamma setting - this should be between 2.2 and 2.8.
It may also be an incorrectly set black or white point - try experimenting with values of between 1% - 4% if possible.
Sharpness - I would expect a little softening in the scan process, but nothing that can't easily be corrected in Photoshop, but the softening should be barely perceptible. An obvious thing to check (but easy to get wrong!) is that the film is the right way round in the scanner. I beleive the Prime supports higher resolutions through interpolation - DON'T use this feature if you want maximum sharpness.
If you can set it, the color space can make a big difference - RGB is probably the default, but sRGB. CIE, Adobe etc. are other possible colour spaces which have a big impact on the final image.
Colin K. Work, Pixstel