well IMHO 3dmark wont give you a even reasonable score inless you have 256mb..
and you need at least 256mb, to even be running 3dmark. i mean if you want a good score anyways. i dont think you can hack 3dmark to use sell memory, cuz most graphics programs need memory to preform well. if i were you, id try a different bench that doesnt need so much memory. like SiSoftSanrda would be good for you to bench with till you get enough memory.