I have the R2400 which is older than the R1900. It works fine with Vista 32 bit and with NX2. If I were you I would download the latest driver from the Epson download site (be sure to choose the 64 bit version) rather than the one on the CD (though the web site says it will work).
8.5 by 11 inches is US Letter size. That's a standard paper size. I don't recognise the others but they're probably standard too. Looking at the Epson store I see they make 8x10 inch size in a few finishes but better to switch over to standard paper sizes.