I bet 512MB of Ram will be the minimum...MTW was 128MB, RTW was 256MB, so probably M2TW will be 512MB of RAM requred...

For MTW my PC was basically at the minimum across the board (I had 350MHz, 128 MB of RAM and a 32MB PCI video card). I could play single player, but at times I would get some lag) I think I was able to play on large units but I am sure I turned down(off) many of the graphics settings.

so as long as you have the minimum you will probably be able to play but I think your 1.5Ghz processer is below the 1.8Ghz required..

I think if you don't play multi player you could get a bottom end computer and it will be fine. I think the main thing is to make sure you have 128MB of video memory. Of course the better card you have the more units you can have on the screen and the higher the graphics settings.