micke: I would take that to mean that if you are running your memory at PC3200 speeds (333mhz), then all 4 banks may be filled, however if you wish to run the memory at pc3200 speeds (400mhz) then you may only fill 2 banks total. With the pc2700 being in there you should be able to fill 3 or 4 banks, with either pc3200 or pc2700 as long as you run the memory at pc2700 (333mhz).
Also, regarding the 939Dual-Sata2, you are right that seems to be no longer available, though it looks like there is a similar model with the same features with model# 939Dual-VSTA.
And with regards to a socket A processor, I just remembered I happen to have an AthlonXP 2800+ 333fsb barton processor that I rescued from a dead computer. As far as I am aware the processor is ok, though I can't say for sure as I don't have a mobo that will take it. I'd be happy to send it to you if you want. I have no use for it.
And as far as a bios upgrade for the cpu to work in the existing mobo, the following link shows the cpus supported by your motherboard cpu support page