For portability : Buy A Laptop HDD of around 160 GB and buy its USB casing...
But id recommend a Sata Hardisk 3.5" with casing cuz in this case you can use your hardisk as a primary hDD also if you choose to..
Keep the rest money for later....
If you want a GFX card than look for no other than 'Point Of View" 8600 GT,, don't get XFX that too from Rashi Peripherals .. it available at your budget but then you'd have to compromise on your Laptop HDD/Pendrive thing
EDIT: You do not need a GFX card if you do not game.. GMA 3100 is more than enough for the visual effects under Windows Vista...
