If you mean 64 bytes by 32, you don't. 
64*32=2048
The arduino only has 1024 bytes of RAM.
EEPROM is only 512 bytes, so that doesn't help.
You could stick it in program memory, but you seem to indicate you want to update it, so that's no use for your application.
If you mean 64 bits by 32, that is possible (256 bytes).
A long is 32 bits; I'd probably use a 2x32 array of unsigned long ints.
-j
Along the lines of array of unsigned ints.. Looks like this should do the trick. (Taken from someones propeller code)
unsigned long displayBitmap[2322];
*2 as I need two colors.
timmaah, I would think using a normal C two-dimensional array would be better for you than to do this yourself.
unsigned long displayBitmap[2*32][2];
It's much more convenient to say displayBitmap[location] than it is to remember displayBitmap[location*2+color] or accidentally get it wrong when you change the number of possible colors. Let the compiler do the addressing math, it might also be able to optimize better than you can.