is this a wireless transfer speed?
if so it is most likely your router. i had this same issue and i transfer a lot of files in my home and a lot of 4.7GB size. i solved it by getting a gigabit router.
if your router is a regular G router than it can only transfer at 54Mb/sec and that is rarely reached because it requires a perfect environment which you are never going to get in the real world. it is normally about half that speed.
if it is an enhanced G then it is possible that it could be rated at 125Mb/sec but again it will most likely run at around half that.
if you had a gigabit router it would be up to 300Mb/sec and again that is not real world.
i think you can see the difference here.
i found that even when i was transferring files to 2 hard wired machines i was not getting the speed i thought i would get until i upgraded to a gigabit router.
google around and check my info and you will find that it is your router that is slowing down your transfers.
also keep in mind that a Mb and a MB are 2 different things. Mb (with a lowercase ‘B’) is short hand for MegaBit. A MB (with an uppercase ‘B’) is short hand for MegaByte. 1 Byte is the same as 8 bits meaning that 1MB is 8Mb. you will find that most devices and internet providers always use the Mb to make their speeds seem faster because the number is bigger