Just had a quick look see and apparently, according to various leaks, looks like it’s been delayed to the second half of 2013 so prices for the 3930k haven’t moved and I would suspect won’t for a while yet. By all accounts the delay may mean that it may overlap the mainstream Haswell chips which may outperform the Ivybridge-E platform which could be a bit of an issue. I’d say that if you wait you’d never upgrade a PC again as there’s always something better just around the corner (I’m looking forward to the first use of carbon nanotubes/graphene in a CPU).
So it is a case of either waiting, after all the system that you currently have isn’t exactly a slouch though after having a closer look you are using the base chipset for Sandy/Ivybridge which doesn’t help matters as it misses out on a few features and performance. Right now I’d go Ivybridge as you could get CPU, motherboard and the SSD for the cost of the 3930k alone then if the Haswell platform isn’t all it is cut out to be and Ivybridge-E’s successor looks like its going to still use the 2011 socket (which is anyone’s guess) then you ebay the guts of your system to pay for an upgrade. Ivybridge won’t disappoint in out and out performance.
As for the whole RAM usability thing (sorry just saw your post above) it’s a case of having a look in the motherboards BIOS so see if it is registering the full amount, the next step is to enable memory remap, as far as I can tell anyway, I’ll admit that I’ve never had this kind of issue myself having built various machines with 8GB and 16GB without a hiccup.