Memory Upgrade for PowerEdge 860

Hi All, this is my first post here, so thanks in advance for any help or advice.

I have a PowerEdge 860, running Server 2003.  Currently I have 4 GB of RAM, but with some farely intensive SQL work, we show about 3.6 GB of that used pretty steadily.  I have been reading through the specs for the hardware and found the user guide states that it can "accommodate 512 MB to 8 GB of unbuffered ECC PC-3200 (DDR2 533 or DDR 667) memory."  I am no memory guru, but I have been searching various suppliers (Softchoice, Memory Express, NCIX, Tiger Direct, etc.) and can't find much for PC-3200 bigger than 1 GB.  My other question is in regards to the reference to DDR2 533 and DDR 667 - Is that a typo, or can the system handle something other than PC-3200?

Thanks again in advance for any help you can offer.

Aaron