I don't quite understand, none of your numbers make sense. 1kb? A0.A6? 256x8 is 2kb and require 8 address lines, not 7. Four 256x8 chips don't need 16 bit address bus-you just need 10 bits.
Maybe what you are trying to say is that you have four 256x8 bit ROMS? In that case you would need address A0-A7 going to the address inputs of all four chips. Then you would decode A8 and A9 to get your 4 chip selects, i.e.
A9 A8
0 0 -->CS0
0 1 --> CS1
1 0 --> CS2
1 1 --> CS3