Yeah, that laptop would work. What I would do is do a fresh install of windows and dont install anything else. Since its a sony it probably has a restore disc, if at all possible don't install any of the extra software that they put on the disc, just windows. You may have to go into add/remove programs and delete some stuff that they are going to put on there anyways. After that you are going to want to your display properties --> appearacne --> effects and turn off the fade effect. I have noticed that it makes slow computers lag just trying to pull up the windows menu and other windows.
And then you are going to want to disable as many services as you can, here is a list of services that are safe to turn off
After that I would install all the programs that you want to use, gps, mp3 player, dvd player, front end, etc. and then see if the computer operates at a speed that is ok with you, try running a couple of programs at the same time, such as mp3 palyback and gps. I would also see if you can put more ram in the machine.