How Getting accounting informations ?

Hi guys, I would like to kkow, how I can get "accounting informations" from my client ? I use a dlink DWL-2000ap+ as NAS (is it compatible ?) and my client is connecting from a windows XP computer. Could you confirm that only the NAS can send accounting informations and not the client...am I right ? If it is, do you know if this dlink is compatible with accounting request ? Do you know another Acces point that sure make this task or is there a software that can be behind my acces point to do this right (a sort of NAS in fact) ? Thanks for your help, Vincent