From what I've been able to ascertain you'd need to update to CS4 or Lightroom 2.6 to get access to the latest Camera Raw version. I believe its also available for PS Elements 8 too.
So theres no conversion to Tiff in that Silkypix software? Seems very limited, what else is wrong with it? The Canon included RAW software is enough to process the exposure and colour balance and reduce noise and lens distortion, then convert to tiff (or others) for external editing.
In my opinion Lightroom 2 is the slickest software, although its not cheap!
EDIT: Just remember user PGTips post about a program called RawTherapee. Just had a look at the supported camera list and the FZ28 is in there, dunno if it has the same .RW2 files but its freeware so won't cost anything to try!
Canon EOS 50D/EF-S 18-55mm IS/EF-S 55250mm IS/EF 50mm F1.8 II /Lowepro AW Slingshot 200/ Digital Ixus 860 IS
PC>Q6700/MSI P45 Zilent/6GB 800mhz DDR2/2x 4870 1GB/Samsung Spinpoint F1 500GB/Maxtor 200GB+80GB