Does the databus size matter for determining the range of the memory addresses?
The data bus width has no correlation to the range of memory addresses. The address bus and the data bus are separate entities. 

For example, if your data bus is 32 bits wide, and your address bus is 16 bits wide, you can have 2^16 memory addresses that are each 32 bits wide. 2^16x32 = 64k x 32bits.

In my example, the lowest memory address is $0000, and the highest memory address is $FFFF. In your example, the lowest would be $00000000 and the highest would be $FFFFFFFF. Each memory address points to a group of bits (32 bits in both of our examples). If you changed your data bus width to 64 bits, and kept your address bus the same width, your memory address span would stay the same. Each address would simply point to 64 bits instead.